Communication device and method used for multi-user spatial modulation

ABSTRACT

A communication device includes a processing circuit, the processing circuit being configured as: mapping a first information bit part used for a receiving end to a corresponding channel based on a pre-set mapping rule so as to execute spatial modulation with respect to the first information bit part of the receiving end; allocating a transmission power to the receiving end; and controlling the transmission power allocated through a mapped channel to transmit a second information bit part used for the receiving end. In the case of the first information bit parts used for multiple receiving ends being the same, the channels mapped for multiple receiving ends are the same. The multi-user spatial modulation performs spatial modulation for multiple receiving ends at the same time through a multiplexing channel of the transmitting end, improving the additional modulation order and the data transmission rate which can be obtained by each receiving end.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/323,588, filed Feb. 6, 2019, which is based on PCT filingPCT/CN2017/106971, filed Oct. 20, 2017, which claims priority to CN201610934492.0, filed Oct. 25, 2016, the entire contents of each areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to transmission techniques inwireless communications, and more particularly to multi-user spatialmodulation techniques in wireless communications.

BACKGROUND ART

Multiple-Input Multiple-Output (MIMO) transmission systems can providemultiplexing gain, diversity gain, and antenna gain. Therefore, thetechnology of MIMO has been applied in many recent communicationstandards, such as IEEE 402.11n, IEEE 402.16, and 3GPP Long-TernEvolution (LTE). However, there exist bottlenecks in the technology ofMIMO in terms of higher complexity and increased hardware cost.

In order to alleviate these drawbacks of MIMO systems while preservingits advantages such as high spectral efficiency, a new modulation methodfor the MIMO systems, called Spatial Modulation (SM), has recently beenproposed. Spatial modulation can reduce system complexity and hardwarecost while maintaining data transmission rate. Spatial modulation can bea new modulation technique in the physical layer mainly because of thefollowing features. First, low complexity and low cost. Forpoint-to-point transmission, only one antenna is activated for datatransmission at any time. This enables spatial modulation while avoidinginter-channel interference. It does not require a synchronizationprocess for multiple antennas, but requires just one RF link, and areceiving end only needs to receive one information flow, so that asimple detection algorithm can be applied directly. Second, additionalmodulation orders. For example, N_(t) antennas can bring an additionalmodulation order of log₂(N_(t)). Therefore, although just one antenna isactivated at each time slice, spatial modulation can still provide avery high data transmission rate.

Spatial modulation can be used for point-to-multipoint multi-usertransmission, and corresponding typical application scenarios include,for example, downlink multi-user transmission in a cellularcommunication system, where the base station is often equipped with alarger number of antennas to facilitate spatial modulation. Therefore,how to realize spatial modulation for point-to-multipoint multi-usertransmission has become one of the research hotspots in this field.

SUMMARY OF THE INVENTION

A summary of the disclosure is set forth below to provide a basicunderstanding of some aspects of the disclosure. However, it should beunderstood that this summary is not an exhaustive overview of thedisclosure. It is not intended to identify key or critical parts of thedisclosure, and not to limit the scope of the disclosure. Its purpose isto present some of the concepts of the present disclosure in asimplified form, as a prelude to a more detailed description givenlater.

According to an aspect of the present disclosure, a communication deviceincluding a processing circuit is provided. The processing circuit isconfigured to: map a first portion of information bits for a firstreceiving end communication device to a first channel and a firstportion of information bits for a second receiving end communicationdevice to a second channel based on a predetermined mapping rule, inorder to perform spatial modulation for the respective first portions ofinformation bits for the first receiving end communication device andthe second receiving end communication device; allocate a firsttransmission power to the first receiving end communication device, andallocate a second transmission power to the second receiving endcommunication device; and controls to transmit, by the first channel atthe first transmission power, a second portion of information bits forthe first receiving end communication device, while controls totransmit, by the second channel at the second transmission power, asecond portion of information bits for the second receiving endcommunication device, wherein the first channel and the second channelare a same channel where the first portion of information bits for thefirst receiving end communication device are the same as the firstportion of information bits for the second receiving end communicationdevice.

According to another aspect of the present disclosure, a communicationdevice including a processing circuit is provided. The processingcircuit is configured to: perform serial interference cancellation (SIC)on received transmission signals, detect signals for other communicationdevices and cancel the detected signals as interference, untilmodulation symbols for the communication device per se are detected anda sequence number of a first channel for transmitting the receivedtransmission signals is detected; and map the sequence number of thefirst channel to a first portion of information bits for thecommunication device per se based on a predetermined mapping rule, anddetermine the second portion of information bits for the communicationdevice per se based on the modulation symbols of the communicationdevice per se.

According to another aspect of the present disclosure, a methodperformed by a communication device is provided. The method includesmapping a first portion of information bits for a first receiving endcommunication device to a first channel and a first portion ofinformation bits for a second receiving end communication device to asecond channel based on a predetermined mapping rule, in order toperform spatial modulation for the respective first portions ofinformation bits for the first receiving end communication device andthe second receiving end communication device; allocating a firsttransmission power to the first receiving end communication device, andallocating a second transmission power to the second receiving endcommunication device; and controlling to transmit, by the first channelat the first transmission power, a second portion of information bitsfor the first receiving end communication device, while controlling totransmit, by the second channel at the second transmission power, asecond portion of information bits for the second receiving endcommunication device, wherein the first channel and the second channelare a same channel where the first portion of information bits for thefirst receiving end communication device are the same as the firstportion of information bits for the second receiving end communicationdevice.

In accordance with another aspect of the present disclosure, a methodperformed by a communication device is provided. The method includesperforming serial interference cancellation (SIC) on receivedtransmission signals, detecting signals for other communication devicesand cancel the detected signals as interference, until modulationsymbols for the communication device per se are detected and a sequencenumber of a first channel for transmitting the received transmissionsignals is detected; and mapping the sequence number of the firstchannel to a first portion of information bits for the communicationdevice per se based on a predetermined mapping rule, and determining thesecond portion of information bits for the communication device per sebased on the modulation symbols of the communication device per se.

According to another aspect of the present disclosure, a communicationdevice including a processing circuit is provided. The processingcircuit is configured to: map a first portion of information bits for afirst receiving end communication device to a first antenna in a firstset of antennas based on a predetermined mapping rule, and a firstportion of information bits for a second receiving end communicationdevice to a second antenna in a second set of antennas, wherein there isat least one common antenna in the first set of antennas and the secondset of antennas; allocate first transmission power to the firstreceiving end communication device, and allocate second transmissionpower to the second receiving end communication device; and transmit, bythe first antenna at the first transmission power, a second portion ofinformation bits for the first receiving end communication device, andtransmit, by the second antenna at the second transmission power, asecond portion of information bits for the second receiving endcommunication device.

According to another aspect of the present disclosure, a communicationmethod is provided, the method comprising: mapping a first portion ofinformation bits for a first receiving end communication device to afirst antenna in a first set of antennas based on a predeterminedmapping rule, and a first portion of information bits for a secondreceiving end communication device to a second antenna in a second setof antennas, wherein there is at least one common antenna in the firstset of antennas and the second set of antennas; allocating firsttransmission power to the first receiving end communication device, andallocating second transmission power to the second receiving endcommunication device; and transmitting, by the first antenna at thefirst transmission power, a second portion of information bits for thefirst receiving end communication device, and transmitting, by thesecond antenna at the second transmission power, a second portion ofinformation bits for the second receiving end communication device.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present disclosure can be achieved byreferring to the detailed description given hereinafter in connectionwith the accompanying drawings, wherein same or similar reference signsare used to indicate same or similar components throughout the figures.The figures are included in the specification and form a part of thespecification along with the following detailed descriptions, forfurther illustrating embodiments of the present disclosure andexplaining the theory and advantages of the present disclosure. Wherein:

FIGS. 1A and 1B are schematic diagrams illustrating an implementationprinciple of spatial modulation (SM) technology and an example of itssignal transmission;

FIG. 2A is a schematic diagram illustrating an example system forapplying SM technology for point-to-point transmission;

FIG. 2B is a schematic diagram illustrating an example system forapplying SM technology for point-to-multipoint transmission;

FIG. 3A is a schematic diagram illustrating an example system forapplying SM technology for point-to-multipoint transmission, accordingto an embodiment;

FIG. 3B is a schematic diagram illustrating an example of the system forapplying SM technology for point-to-multipoint transmission, accordingto an embodiment herein;

FIG. 3C is another schematic diagram illustrating the example of thesystem for applying SM technology for point-to-multipoint transmission,according to an embodiment herein;

FIG. 4A is a functional configuration block diagram illustrating anexample of a transmitting end communication device for applying SMtechnology for point-to-multipoint transmission, according to anembodiment herein;

FIG. 4B is a flowchart illustrating an example of a transmitting endmethod for applying SM technology for point-to-multipoint transmission,according to an embodiment herein;

FIG. 5A is a functional configuration block diagram illustrating anexample of a receiving-side communication device for applying SMtechnology for point-to-multipoint transmission, according to anembodiment herein;

FIG. 5B is a flowchart illustrating an example of a receiving end methodfor applying SM technology for point-to-multipoint transmission,according to an embodiment herein;

FIG. 6 is a schematic diagram illustrating another example system forapplying SM technology for point-to-multipoint transmission, accordingto an embodiment herein;

FIG. 7 is a schematic diagram illustrating another example system forapplying SM technology for point-to-multipoint transmission, accordingto an embodiment herein;

FIG. 8 is a diagram illustrating an example mapping rule of informationbits and antenna numbers for applying SM technology forpoint-to-multipoint transmission, according to an embodiment herein;

FIG. 9 is a flowchart illustrating an exemplary method of performingsignal detection at a receiving end by using a Maximum Likelihood (ML)algorithm, according to an embodiment herein;

FIG. 10 is a flowchart illustrating an exemplary method of performingsignal detection at the receiving end by using a Maximum Ratio Combining(MRC) algorithm, according to an embodiment herein;

FIG. 11 is a flow diagram illustrating an example process of signalinteraction for applying SM technology for point-to-multipointtransmission, according to an embodiment herein;

FIGS. 12A to 12D are schematic diagrams illustrating bit error rateperformance of point-to-multipoint transmission by SM technology,according to an embodiment herein;

FIG. 12E is a schematic diagram illustrating a comparison of bit errorrate performance between low complexity power allocation andmulti-dimensional grid search power allocation, according to anembodiment herein;

FIG. 13 is a block diagram of example structure of a personal computerwhich is an information processing device that can be employed in anembodiment herein;

FIG. 14 is a block diagram illustrating a first example of a schematicconfiguration of an evolved Node B (eNB) to which the technology hereincan be applied;

FIG. 15 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology herein can be applied;

FIG. 16 is a block diagram illustrating an example of a schematicconfiguration of a smartphone to which the technology herein can beapplied; and

FIG. 17 is a block diagram illustrating an example of a schematicconfiguration of a automobile navigation device to which the technologyherein can be applied.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments herein will be described in detail withreference to the accompanying drawings. Note that, in the presentspecification and the drawings, the structural elements that havesubstantially the same function and structure are denoted by the samereference numerals, and the repeated description of these structuralelements is omitted.

Exemplary embodiments of the present disclosure will be describedhereinafter with reference to the accompanying drawings. For the sake ofclarity and conciseness, not all features of a actual implementation aredescribed in the specification. However, it should be appreciated thatimplementation specific decisions must be made in the development of anysuch actual embodiment, so as to achieve specific goals of thedeveloper. For example, to comply with constrain conditions related tosystem and business, and these constrain conditions may vary fromimplementation to implementation. Furthermore, it will also beappreciated that the development work may be more complicated and timeconsuming, although such development work is merely a routine task forthose skilled in the art having benefit of this disclosure.

Only the device structure and/or operational steps closely related tothe solutions according to the present disclosure are shown in thedrawings in order to avoid obscuring the present disclosure withunnecessary detail, and other details that has little relation to thepresent disclosure are omitted.

First, the basic principles of SM technology and its implementation insome examples in point-to-point and point-to-multipoint transmissionscenarios are briefly introduced with reference to FIGS. 1A-2B.

The basic idea of SM is to map the information bits to be transmittedinto two types of information, namely amplitude phase modulation symbols(depending on the specific modulation method) and a sequence number ofan antenna (or a channel). FIG. 1A is a schematic diagram illustratingan example of implementation principle of SM technology. According tothe principle, a first portion of information bits to be transmitted aremapped to the sequence number of the antenna, and a second portion ofinformation bits to be transmitted are mapped to the modulation symbols.As shown in the example of FIG. 1A, for information bits “101” to betransmitted from an information flow, for example, two bits “10” of theinformation bits are mapped to the sequence number of the antenna (here,for example, Tx2, i.e., the third antenna), for example, another bit “1”of the information bits is mapped to the modulation symbol “−1”(assuming that the modulation method here is Binary Phase Shift Keying(BPSK)). Therefore, the total modulation order B can be expressed as:B=log₂(N_(t))+log₂(M), where N_(t) represents a total number of theantennas, and M represents a number of modulation symbols of a certainmodulation scheme. For example, for BPSK, M is 2, and for quadraturephase shift keying (QPSK), M is 4. It can be seen that in SM of thisexample, only one antenna transmits signals at each time slice, whiletransmission power of the other antennas is zero. By mapping a portionof information bits to a selected antenna, although only one antenna isactivated in one time slice, a higher data transmission rate can stillbe achieved.

During the transmission of signals from the antennas to the receivingend via the wireless channel, signals emitted from different antennasmay experience different propagation models due to different spatialpositions of the respective antennas in an antenna array. FIG. 1B is aschematic diagram illustrating an example of signal transmission towhich SM technology is applied. As shown in the example of FIG. 1B,assuming that a signal is transmitted through, for example, the antennaTx2 at this time, the transmission powers on the antennas Tx0, Tx1, andTx3 are all zero at this time, and a waveform of the signal received atthe receiving end corresponds to that of wireless channel correspondingto the antenna Tx2, thus the receiving end can perform signaldemodulation based on the received signals according to a correspondingsignal detection algorithm (for example, MRC detection algorithm). Thatis, information bits mapped to the sequence numbers of antennas andinformation bits mapped to modulation symbols are respectivelydemodulated.

FIG. 2A is a schematic diagram illustrating an example system forapplying SM technology for point-to-point transmission. In the exampleof FIG. 2A, antennas in a set of antennas (assuming N_(t) antennas) atthe transmitting end are all used for SM for a single receiving end. Inthe example system, the additional modulation order obtained by thereceiving end for indicating the information bits to be transmitted byusing the sequence number of the activated antenna can be expressed aslog₂(N_(t)).

When applying SM technology for point-to-multipoint transmission, suchas in a downlink multi-user transmission scenario of a cellularcommunication system, an exemplary way is to group the set of antennasat the transmitting end (e.g., a base station). FIG. 2B is a schematicdiagram illustrating an example system for applying SM technology forpoint-to-multipoint transmission. In the example of FIG. 2B, for Kreceiving ends, N_(t) antennas, for example, are divided into K groups,and each group of N_(t)/K antennas are dedicated to SM for a particularsingle receiving end. It is not difficult to find that in the examplesystem of FIG. 2B, just the additional modulation orderlog₂(N_(t)) inthe point-to-point transmission scenario of FIG. 2A is directly dividedinto K shares, and each receiving end obtains one share

$\left( {i.e.\mspace{14mu} {\log_{2}\left( \frac{N_{t}}{K} \right)}} \right)$

of the additional modulation order.

In the example system of FIG. 2B, in order to performpoint-to-multipoint transmission, antenna resources at the transmittingend are simply allocated to multiple receiving ends, the additionalmodulation order obtained by each receiving end is limited, andimprovement in data transmission rate is not that significant. Since thenumber of antennas at the transmitting end is limited, the abovedrawback becomes increasingly obvious as the number of the receivingends increases.

In the above example system of point-to-multipoint transmission, the SMfor the multiple receiving ends can be regarded as orthogonal, that is,any antenna that is currently activated is dedicated to only onereceiving end, which limits the additional modulation order eachreceiving end can obtained and the data transmission rate increasement.A communication device and method for non-orthogonal multi-user spatialmodulation (SM) will be described below, wherein the transmitting end iscapable of multiplexing antennas (channels) with same radio transmissionresource (e.g., physical resource blocks in LTE) to perform SM formultiple receiving ends simultaneously. That is, there is at least oneantenna at the transmitting end that can be used for multiple receivingends, such that the additional modulation order each receiving end canobtained and the data transmission rate can be greatly improved. Beforeintroducing the non-orthogonal multi-user SM, the following aspects areclarified.

First, in SM, a portion of information bits are mapped to the sequencenumber of the antenna, and another portion of the information bits aremapped to modulation symbols and transmitted by the antenna representedby the sequence number. The mapping of information bits to antennasequence numbers actually selects the antenna from which the modulationsymbols are transmitted, that is, the channel on which the modulationsymbols are transmitted. The terms “antenna” and “channel” are usedinterchangeably in the context herein due to the correspondence betweenthe antenna and the channel. In the following description of theembodiments herein, although the term “antenna” is used more often, itwill be apparent to those skilled in the art that the term “channel” canalternatively be used.

Secondly, in the embodiments herein, the term “antenna” can have itsbroadest meaning in the art. For example, an antenna can refer to asingle physical antenna or a virtual antenna. The antenna can also havea similar meaning to an antenna port in the LTE standard, which cancorrespond to the transmission of a reference signal. That is, in thecase where a same reference signal is transmitted from one or morephysical antennas, the one or more physical antennas correspond to asingle antenna port; similarly, in the case where two differentreference signals are transmitted from one or more physical antennas,the one or more physical antennas correspond to two separate antennaports. Those skilled in the art can clarify other meanings that the termantenna can have according to teachings of the present disclosure.

For example, in Chinese Patent Application No. 201610404821.0, entitled“Electronic Device and Method for Multi-Antenna CommunicationApparatus”, filed on Jun. 8, 2016, it proposed a method to reconstruct aphysical channel to obtain a reconstructed channel, so that there is lowcorrelation between the reconstructed channels, which is incorporatedherein by reference in its entirety. Assuming that any two actualphysical channels from the transmitting end to the receiving end are h₁and h₂, respectively, and channel vectors of the two channels havestrong correlation (i.e., the phase difference between the two issmall), this will make performance of traditional SM technologydegraded. According to the technology in the cited application, the twoactual physical channels can be reconstructed using reconstructionparameters [α₁, α₂], such that correlation between the reconstructedchannels is reduced (i.e., the phase difference between thereconstructed channel vectors is increased), and preferably, thereconstructed channels are orthogonal to each other, that is, {tildeover (h)}₁⊥{tilde over (h)}₂, wherein, {tilde over (h)}₁=α₁, ₁h₁+α₁,₂h₂, {tilde over (h)}₂=α₂, ₁h₁+α₂, ₂h₂, then correlation between thereconstructed channels is minimized. According to the application, alltransmit antennas are activated at each time slice, and each transmitantenna can be configured according to corresponding reconstructionparameters, in order to achieve channel reconstruction. Thus, in theembodiments herein, the term “antenna” can alternatively be a group ofphysical or virtual antennas corresponding to a reconstructed channel.

An example system for applying SM technology for point-to-multipointtransmission will be described below with reference to FIG. 3A.

In the multi-user SM system 300A according to an embodiment herein shownin FIG. 3A, there are N_(t) (where N_(t)≥2) antennas in the antenna set330 at the transmitting end (e.g., base station) 310, and these antennasform a RF channel to perform downlink data transmission for multiplereceiving ends (for example, K receiving ends 1 to K). In oneembodiment, the receiving end can be a user equipment in a cell of acellular communication system. In the multi-user SM system 300A, at anytime slice, any antenna in the antenna sets 330 at the transmitting end310 can be multiplexed by multiple of the K receiving ends 1 to K forSM. In other words, for any of all the K receiving ends, any of theN_(t) antennas can be selected to transmit signals, that is, all theN_(t) antennas can be used as candidates. This is in contrast to theexample system as shown in FIG. 2B, where a separate set of antennascorrespond to each receive end. For example, for the receiving end 1 inFIGS. 2B and 3A, only antennas in the first set of antennas at thetransmitting end can be used to transmit signals to the receiving end inFIG. 2B, and any antenna at the transmitting end can be used to sendsignals to the receiving end in FIG. 3A. As indicated, the transmittingand receiving ends in this example can correspond to the base stationand user equipment in the cellular communication system, respectively.To be noted, however, in this example and the alternative examplesdescribed below, the transmitting end can also correspond to anyelectronic device (e.g., a personal electronic device) that needs tosend information to multiple devices at the other end, and the receivingend can correspond to the devices at the other end (e.g., also apersonal electronic device).

FIG. 4A is a functional configuration block diagram illustrating anexample of a transmitting end communication device for applying SMtechnology for point-to-multipoint transmission, according to anembodiment herein. The transmitting end communication device 400 can bean example of the communication device at the transmitting end 310 inFIG. 3A. As shown in FIG. 4, in one embodiment, the transmitting endcommunication device 400 can include a SM mapping unit 402, a powerallocation unit 404, and a transmission control unit 406.

The SM mapping unit 402 can be configured, for example, to map a firstportion of information bits for a first receiving end communicationdevice (e.g., receiving end 1) to a first channel (e.g., a channelcorresponding to a first antenna in the antenna set 330) and to map afirst portion of information bits for a second receiving endcommunication device (e.g., receiving end 2) to a second channel (e.g.,a channel corresponding to a second antenna in the antenna set 330)based on a predetermined mapping rule, in order to perform spatialmodulation for the first portions of information bits for the firstreceiving end communication device (e.g., receiving end 1) and thesecond receiving end communication device (e.g., receiving end 2).

The power allocation unit 404 can be configured, for example, toallocate a first transmission power to the first receiving endcommunication device (e.g., receiving end 1) and a second transmissionpower to the second receiving end communication device (e.g., receivingend 2).

The transmission control unit 406 can be configured, for example, tocontrol to transmit, by the first channel (e.g., the channelcorresponding to the first antenna in the antenna set 330) at the firsttransmission power, a second portion of information bits for the firstreceiving end communication device (e.g., receiving end 1), whilecontrol to transmit, by the second channel (e.g., the channelcorresponding to the second antenna in the antenna set 330) at thesecond transmission power, a second portion of information bits for thesecond receiving end communication device (e.g., receiving end 2).

In the case where the first portion of information bits for the firstreceiving end communication device (e.g., receiving end 1) and the firstportion of information bits for the second receiving end communicationdevice (e.g., receiving end 2) are the same, the first channel and thesecond channel can be a same channel (e.g., a channel corresponding tothe same antenna in the antenna set 330). In other words, the samechannel or the same antenna can be multiplexed simultaneously bydifferent receiving end communication devices.

One or more of the SM mapping unit 402, the power allocation unit 404,and the transmission control unit 406 can be implemented by a processingcircuit. Here, a processing circuit can refer to various implementationsof digital circuitry, analog circuitry, or mixed signal (combination ofanalog and digital) circuitry that perform functions in a computingsystem. Processing elements can include, for example, circuits such asintegrated circuits (ICs), application specific integrated circuits(ASICs), portions or circuits of individual processor cores, entireprocessor cores, separate processors, programmable hardware devices suchas field programmable gate arrays (FPGAs), and/or a system includingmultiple processors.

It will be appreciated that the transmitting end communication device400 can be implemented at the chip level or can be implemented at thedevice level by including other external components. For example, thetransmitting end communication device 400 can operate as a multi-antennacommunication device as a whole machine, and the transmitting endcommunication device 400 can also include a plurality of antennas.

It should further be understood that the various units described aboveare merely logical functional blocks that are divided according to thespecific functions implemented, and it is not intended to limit them tothe particular implementation. In actual implementation, each of theabove functional units can be implemented as a separate physical entity,or can be implemented by a single entity (eg, a processor (CPU or DSP,etc.), an integrated circuit, etc.).

Exemplary operations performed by the communication device 400 at thetransmitting end 310 are described in detail below in conjunction withthe flowchart of FIG. 4B.

At any time slice, at the communication device 400 at the transmittingend 310, for any of the K receiving ends (e.g., at least one of thefirst receiving end communication device and the second receiving endcommunication device), the information bits (i.e., the first portion ofinformation bits) in a first information flow for the receiving end aremapped to a respective antenna based on the predetermined mapping rule,in order to perform SM on the information bits (step 401). For example,based on the predetermined mapping rule, the first portion ofinformation bits for the receiving end 1 can be mapped to the firstantenna in the antenna set 330, and the first portion of informationbits for the receiving end 2 can be mapped to the second antenna in theantenna set 330, and so on, the first portion of information bits forthe receiving end k can be mapped to a kth antenna in the antenna set330. Here, for the first, second and kth antennas, there can be at leasttwo antennas that are a same antenna with a same antenna sequence number(e.g., the first portions of the information bits for the receiving ends1 and 2 are the same), or can be at least two antennas that aredifferent antenna with different antenna sequence numbers (e.g., thefirst portions of information bits for the receiving ends 1 and 2 aredifferent). Step 401 can be performed, for example, by the SM mappingunit 402 of the communication device 400 at transmitting end 310.

The above predetermined mapping rule is a rule that specifies acorrespondence between information bits and an antenna (channel) to beselected for transmission of information, e.g., as shown in the exampleof FIG. 8. FIG. 8 is a diagram illustrating an example mapping rule 800of information bits and antenna sequence numbers for applying SMtechnology for point-to-multipoint transmission, according to anembodiment herein. In the example in FIG. 8, according to the mappingrule 800, when the first information bits for the receiving end are, forexample, 00, 01, 10, and 11, respectively, the first information bitsare respectively mapped to the antennas with a sequence number 1, 2, 3,4, respectively. It should be understood that the number of informationbits that can be mapped to the antenna number is related to the numberof antennas N_(t) at the transmitting end. For example, if there are 4antennas, the number of information bits that can be mapped to eachantenna is 2 bits; if there are 8 antennas, the number of informationbits that can be mapped to each antenna is 3 bits. That is, the numberof information bits that can be mapped can be expressed as log₂N_(t).Therefore, the embodiments herein are especially suitable for millimeterwave (mmWave) communication scenarios where a large number of antennascan be deployed. However, the application of the present disclosure isnot limited thereto, and there is no limitation on the applied frequencyband.

It should be noted that the mapping rule 800 of information bits andantenna numbers in FIG. 8 is merely exemplary. Different mapping rulescan be predetermined for a specific number of antennas, for specifyingthe mapping between the information bits and the antenna numbers, aslong as the transmitting end and each receiving end agree on the mappingrule. The mapping relationship can be stored in storage devices at thetransmitting end and the receiving end, and can be statically configuredor dynamically updated according to information such as channel status.For example, in one embodiment, the transmitting end communicationdevice 400 can further include a memory that can be configured to storepredetermined mapping rules for reading by a processing circuit, themapping rule can specify the mapping between the information bits andthe antenna sequence numbers.

According to an embodiment, the predetermined mapping rules applied bydifferent receiving ends can be the same, such that if the first portionof information bits for the receiving end 1 and the first portion ofinformation bits for the receiving end 2 are the same (for example, bothare information bits 00 shown in FIG. 8), the mapped first antenna andsecond antenna can be the same antenna (for example, the antenna withsequence number 1 in FIG. 8). According to another embodiment, differentreceiving ends can apply different predetermined mapping rules, suchthat if the first portion of information bits for the receiving end 1and the first portion of information bits for the receiving end 2 arethe same, the mapped first antenna and second antenna can be differentantennas; if the first portion of information bits for the receiving end1 and the first portion of information bits for the receiving end 2 aredifferent, the mappled first antenna and second antenna can still be thesame antenna, as long as the transmitting end and each receiving endreach an agreement on the predetermined mapping rule. In this latterembodiment, only receiving ends that reach the agreement with thetransmitting end on the specific mapping rule can determine the correctantenna sequence number, which can be beneficial to improve security ofinformation transmission.

In one embodiment, information bits in the second information flow(i.e., a second portion of information bits) for the receiving end arefurther mapped to particular modulation symbols, in order to performmodulation for the information bits (e.g., the amplitude phasemodulation, frequency modulation, or other types of modulation).According to an embodiment, a particular modulation symbols can be, forexample, a particular amplitude phase modulation symbol (i.e., aconstellation point in the constellation) in the amplitude phasemodulation scheme, in order to perform amplitude phase modulation forthe information bits (step 407). In one embodiment, the particularamplitude phase modulation scheme can depend on channel stateinformation at the receiving end (eg, a receiving signal to noise ratioSNR condition at the receiving end), for example, a higher receiving SNRcan correspond to a higher order modulation scheme; vice versa. Here,the amplitude phase modulation includes any modulation scheme thatmodulates at least one of the amplitude and phase of a carrier totransmit data, such as, but not limited to, BPSK, QPSK, 2ASK, 4ASK, or16QAM, and the like. Step 407 can be performed, for example, by the SMmapping unit 402 of the communication device 400 at the transmitting end310. It is noted that although step 407 is shown in FIG. 4 as beingperformed in parallel with step 401, in other embodiments, step 407 canalso be performed before or after step 401.

It should be noted that, at the transmitting end, the first and secondinformation flows of the multiple receiving ends can have multiplesources. In one embodiment, the first and second information flows atthe receiving end of FIG. 3A can be from the same source of informationbut split into two information flows in a particular manner. In anotherembodiment, source information (such as a small number of, but importantinformation, such as a security key) can not be split, but all enteredinto the first information flow. Then, the second information flow canbe information bits that are not to be transmitted, but all 1, all 0 orany auxiliary information bits. That is, in this embodiment, only thefirst information flow is transmitted by using system 300A. In stillother embodiments, if the transmitting end desires to transmit voice orapplication data to the receiving end, it may be desirable to encryptthe voice or application data with a security key to enhance security.Then, the encrypted voice or application data to be transmitted is usedas the second information flow, and the security key for encrypting thevoice or application data is used as the first information flow, theinformation bits corresponding to the security key are mapped to theantenna sequence number by the SM technology herein. In the latter twocases, communication security can be guaranteed to a certain extent.

Therefore, in one embodiment, the transmitting end communication device400 can further include a slicing unit 408 that splits the data to betransmitted for the first and second receiving end communication devicesinto first portion of information bits and second portion of informationbits for transmission, wherein the length of the first portion ofinformation bits is related to the value of N_(t). Alternatively, thetransmitting end communication device 400 can not include the slicingunit 408. Then, the information flow to be transmitted can correspond tothe first information flow of each receiving end in FIG. 300A, and thesecond information flow can be not the modulated data, but all 1, all 0or any bit signals. This can be applied to use the first informationflow to carry little volume but important information in, for example,military applications to improve security. It should be clear to thoseskilled in the art that the receiving end needs to perform processingcorresponding to the transmitting end after restoring the informationbits in the first information flow and the second information flow. Forexample, if the first information flow and the second information floware obtained by slicing the source information, it is necessary toperform corresponding combination processing on the information bits inthe restored first and second information flows at the receiving end.

At the communication device 400 at the transmitting end 310, thetransmission power is allocated to the receiving ends, thereby forming atransmission power allocation result (step 403). For example, the firstreceiving end communication device (e.g., the receiving end 1) can beallocated with a first transmission power and the second receiving endcommunication device (e.g., the receiving end 2) can be allocated with asecond transmission power. Step 403 can be performed, for example, bythe power allocation unit 404 of the communication device 400 at thetransmitting end 310.

According to an embodiment, the transmission power allocation result canbe calculated according to a transmission power allocation principle,which can include one or more of the following: allocating a lowertransmission power to a receiving end communication device closer to thetransmitting end; allocating a lower transmission power to a receivingend communication device with higher receiving SNR; allocating a highertransmission power to a receiving end communication device with a higherdata rate demand; and causing the receiving SNRs of all receiving endcommunication devices to be at the same level. For example, according toa principle, assuming that the radio channel condition of the receivingend 2 is better than that of the receiving end 1, in order to enable thetwo receiving ends to detect signals for themselves, a largertransmission power is allocated to the receiving end 1, for examplep₁=0.8, and a smaller power, for example, p2=0.2 is allocated to thereceiving end K (assuming the total power is 1), such that signals aretransmitted based on this transmission power allocation. Althoughseveral specific examples of the power transmission allocation principleare given above, the power transmission allocation principle is notlimited to these specific examples, and those skilled in the art candesign other power transmission allocation principles according toactual application and design requirements.

In one embodiment, the transmission power allocation result can includeinformation indicating an absolute value or a relative value indicatingtransmission power allocated to each of all the receiving ends. Inanother embodiment, the transmission power allocation result can includeinformation indicating an order of transmission power allocated to atarget receiving end or demodulation order. This order or demodulationorder information can be informed to the corresponding receiving end. Inone embodiment, the transmission power allocation result can be includedin the physical layer downlink control information, for example, in thescheduling information, and in particular can be carried by, forexample, a PDCCH channel in LTE.

In one embodiment, the transmission power is allocated in accordancewith a transmission power allocation result that is pre-computed andstored for a particular transmission power allocation principle; inanother embodiment, the transmission power allocation result iscalculated in real time for transmission power allocation. Therefore,the transmitting end can read the power allocation parameter from thesystem preset information table, or can choose to adjust the powerallocation in real-time through the user feedback information, whichdepends on the processing capability of the transmitting end. It can beseen that off-line computing can reduce the computational load at thetransmitting end compared to real-time computing solutions.

Next, the communication device 400 at the transmitting end 310 controls,based on the mapping performed in step 401, to transmit the secondportion of information bits for each receiving end by the mapped antennaat the corresponding transmission power (step 405). For example, controlis performed to transmit the second portion of information bits for thereceiving end 1 by the first antenna in the antenna set 330 at the firsttransmission power, and control is performed to transmit the secondportion of information bits for the receiving end 2 by the secondantenna in the antenna set 330 at the second transmission power, and soon, control is performed to transmit the second portion of informationbits for the receiving end k by the kth antenna in the antenna set 330at the kth transmission power. Step 407 can be performed, for example,by the transmission control unit 406 of the communication device 400 atthe transmitting end 310.

If the first portions of information bits for the multiple receivingends (for example, the receiving end 1 and the receiving end 2) are thesame (for example, both are the information bits 00 in FIG. 8), portionsof information bits in the second information flows for the multiplereceiving ends can be simultaneously superimposed and transmitted by thesame mapped antenna (for example, by the same antenna with the sequencenumber 1 in FIG. 8). As indicated earlier, there is a correspondencebetween the antennas and the channels. Therefore, those skilled in theart will understand that mapping information bits to an antenna here isto map information bits to a channel corresponding to the antenna, andtransmitting information bits by the antenna is to transmit informationbits by a channel corresponding to the antenna.

Examples of the exemplary system described in FIG. 3A are describedbelow in conjunction with FIGS. 3B and 3C.

FIG. 3B is a schematic diagram illustrating one example of the exemplarysystem for applying SM technology for point-to-multipoint transmission,according to one embodiment herein. In this example, the transmittingend can, for example, have 4 antennas (i.e. N_(t)=4). As shown in theexample of FIG. 3B, at the transmitting end 310, each 2 bits in thefirst information flow for the receiving end are mapped to the antennanumbers based on predetermined mapping rules. In this example, thepredetermined mapping rule can be the mapping rule 800 as shown in FIG.8. At the transmitting end 310, the transmission power is also allocatedto the receiving ends to form a transmission power allocation result.Next, the information bits in the second information flow for all themultiple receiving ends are respectively mapped to antennas according tothe mapping rule 800 for transmission in a superimposing manner.

In this example, according to the receiving SNR at the receiving end,the amplitude phase modulation is performed on each bit in the secondinformation flow for the receiving end by using the BPSK modulationscheme (i.e., the constellation point symbols are +1 and −1), and thebits are transmitted by the antenna represented by the above mappedsequence number. For example, a message “101” is to be transmitted tothe receiving end 1. According to the mapping rule 800, for thereceiving end 1, 2 bits “10” in the first information flow are mapped tothe third antenna, and 1 bit “1” in the second information flow ismapped to the BPSK modulation symbol “−1”, then the transmission signalvector for the receiving end 1 is [0 0 −1 0]^(T). In this vector, “−1”represents the modulation symbol whose position in the vectorcorresponds to the mappled antenna. In this example, the third antennais used for signal transmission, and the power for each of the otherthree antennas is zero. Further, for example, a message “100” is to betransmitted to the receiving terminal K. For the receiving end K, the 2bits “10” in the first information flow are also mapped to the thirdantenna, and the 1 bit “0” in the second information flow is mapped tothe BPSK modulation symbol “1”, then the transmission signal vector forthe receiving end K is [0 0 1 0]^(T). The meaning of the vector can beunderstood similarly to the above. It is not difficult to see that,since the bits (the first information bits) of the first informationflow for the receiving end 1 and the bits (first information bits) ofthe first information flow for the receiving end K are the same (here,both are 10), therefore, the modulation signals for the receiving end 1and the receiving end K will be transmitted by the same antenna (i.e.,the third antenna) to which the first information bit is mapped.

It should also be noted that if the information bits in the firstinformation flows for the receiving end 1 and the receiving end K aredifferent, the antennas mapped or selected according to the mapping rule800 as shown in FIG. 8 can be different, which is similar to the case inthe example of FIG. 3C. FIG. 3C is another schematic diagramillustrating the system of FIG. 3B for applying SM technology forpoint-to-multipoint transmission, according to one embodiment herein.For example, if a message “101” is to be transmitted to the receivingend 1, and the message “110” is to be transmitted to the receiving endK, according to the mapping rule 800 shown in FIG. 8, the 2 bits “10” inthe first information flow for the receiving end 1 are mapped to thethird antenna, and the 2 bits “11” in the first information flow for thereceiving end K are mapped to the fourth antenna. Accordingly, since thebits (the first information bits) of the first information flow for thereceiving end 1 and the bits (the first information bits) of the firstinformation flow for the receiving end K are different, the respectiveone bit in the second information flows for the two receiving ends willbe transmitted by different antennas respectively.

FIG. 5A is a functional configuration block diagram illustrating anexample of a receiving end communication device for applying SMtechnology for point-to-multipoint transmission, according to anembodiment herein. The receiving end communication device 500 can be anexample of the communication device at any receiving end k of FIG. 3A.As shown in FIG. 5A, in one embodiment, the receiving end communicationdevice 500 can include a detection unit 504 and a spatial demodulationmapping unit 502.

The detection unit 504 of the receiving end k can, for example, beconfigured to perform serial interference cancellation (SIC) on receivedtransmission signal, detect signals for other receiving endcommunication devices (e.g., the receiving end 1, receiving end K, etc.)and cancel the detected signal as interference, until a modulationsymbol for the communication device per se (i.e., the receiving end k)is detected and a sequence number of the first channel (e.g., thechannel corresponding to the first antenna in the antenna set 330) thattransmitted the received transmission signal is detected.

The spatial demodulation mapping unit 502 of the receiving end k can,for example, be configured to map the sequence number of the firstchannel (e.g., the channel corresponding to the first antenna in theantenna set 330) to the first portion of information bits for thecommunication device per se (i.e., the receiving end k) based on thepredetermined mapping rule (e.g., the mapping rule 800 as shown in FIG.8), and determine the second portion of information bits for thecommunication device per se (i.e., the receiving end k) based on themodulation symbols for the communication device per se.

One or more of the detection unit 504 and the spatial demodulationmapping unit 502 can be implemented by a processing circuit. Here, aprocessing circuit can refer to various implementations of digitalcircuitry, analog circuitry, or mixed signal (combination of analog anddigital) circuitry that perform functions in a computing system.Processing elements can include, for example, circuits such asintegrated circuits (ICs), application specific integrated circuits(ASICs), portions or circuits of individual processor cores, entireprocessor cores, separate processors, programmable hardware devices suchas field programmable gate arrays (FPGAs), and/or a system includingmultiple processors.

It will be appreciated that, similarly, the receiving end communicationdevice 500 can be implemented at the chip level, or can also beimplemented at the device level by including other external components.For example, the receiving end communication device 500 can operate as awhole device as a communication device, and can also include one or moreantennas.

It should further be understood that the various units described aboveare merely logical functional blocks that are divided according to thespecific functions implemented, and it is not intended to limit them tothe particular implementation. In actual implementation, each of theabove functional units can be implemented as a separate physical entity,or can be implemented by a single entity (eg, a processor (CPU or DSP,etc.), an integrated circuit, etc.).

Exemplary operations performed by, for example, the communication device500 at the receiving end k are described in detail below in conjunctionwith the flowchart of FIG. 5B.

At the communication device 500 at the receiving end k, SIC is performedon the transmission signal received from the transmitting terminal 310to detect signals for other receiving ends and cancel the signals forother receiving ends as interference, until a signal for the receivingend per se is detected (step 501). In one embodiment, the signal for thereceiving end k per se can include a modulation symbol for the receivingend and a sequence number of the first channel that transmitted thereceived transmission signal. It can be understood that the sequencenumber of the first channel can correspond to the sequence number of aspecific antenna (for example, the first antenna). Step 501 can beperformed, for example, by the detection unit 504 of the communicationdevice 500 at the receiving end k.

In one embodiment, at the communication device 500 at the receiving endk, information is received indicating the order of the transmissionpower used by the first antenna in transmitting the signal for thereceiving end per se among the transmission powers used in transmittingsignal for all receiving end communication devices (for example,including the receiving end 1, the receiving end K, etc.), wherein thenumber of times the SIC is performed depends on the order. In oneembodiment, in the SIC, signals for other communication devices aredetected by a detection algorithm, including the ML algorithm or the MRCalgorithm. The process of the SIC can be referred to the description,for example, with respect to FIGS. 9-10.

In one embodiment, the sequence number of the first channel can bedetected based on the channel state information, which can be determinedby the receiving end k based on training sequences transmitted by thefirst antenna.

At the communication device 500 at the receiving end k, spatialdemodulation is performed on the signal for the receiving end k per se(step 503). In one embodiment, the operation in step 503 includes, insub-step 503 a, mapping the sequence number (e.g., “1”) of the firstchannel by which the received transmission signal is transmitted to thefirst portion of information bits (e.g., “00”) for the receiving end kper se based on a predetermined mapping rule (e.g., the mapping rule 800as shown in FIG. 8). In another embodiment, the operation in step 503further includes, in sub-step 503 b, mapping the modulation symbols forthe receiving end k to the second portion of information bit s for thereceiving end k, according to the corresponding amplitude phasemodulation scheme. Step 503 can be performed, for example, by thespatial demodulation mapping unit 502 of the communication device 500 atthe receiving end k.

In one embodiment, according to the mapping rule 800 shown in FIG. 8,when the sequence numbers of the first channels on which the receivedtransmission signals are transmitted are, for example, 1, 2, 3, 4,respectively, the channel sequence numbers are accordingly mapped to thefirst portions of information bits with bit values of 00, 01, 10, and11, respectively. Accordingly, in one embodiment, the receiving endcommunication device 500 can further include a memory configured tostore predetermined mapping rules for reading by a processing circuit,and the mapping rule can specify a mapping between information bits andantenna sequence numbers.

In one embodiment, at the communication device 500 at the receiving endk, information about the amplitude phase modulation scheme is received,and the second portion of information bits for the receiving end k perse is determined by using the amplitude phase modulation schemeindicated by such information.

In an embodiment, after the first portion of information bits and thesecond portion of information bits are restored, the receiving end kneeds to perform processing corresponding to the transmitting end onthem. For example, in the case where the first portion of informationbits and the second portion of information bits are obtained bysplitting the source information at the transmitting end, it isnecessary to combine the first portion of information bits for thereceiving end per se with the second portion of information bits for thereceiving end to obtain the original transmission data flow. Forexample, in one implementation, the receiving end communication device500 can further include a combining unit 508 that combines the firstportion of information bits for the communication device per se and thesecond portion of information bits for the communication device per seinto the original transmission data flow.

It should be understood that the functional configurations of thecommunication devices shown in FIG. 4A and FIG. 5A are merely examples,and those skilled in the art can modify the above functionalconfigurations according to the principles of the present disclosure,for example, combining the above functional units, adding, deleting,and/or changing some functional units. In addition, in order to avoidobscuring the present invention, descriptions of some well-knownfunctional units and their operations are omitted in the description ofthe embodiment of FIGS. 4A and 5A, but these are easily implemented bythose skilled in the art in accordance with the principles of thepresent disclosure and well-known knowledge in the art.

In addition, it should be noted that the flowcharts shown in FIG. 4B andFIG. 5B are only examples and are non-limiting, and those skilled in theart can also make various modifications according to the principles ofthe present disclosure, such as adjusting the execution of the abovemethod flow, deleting/adding some steps, etc.

In the above non-orthogonal multi-user SM, the transmitting endmultiplexes the antennas to perform SM for the multiple receiving endssimultaneously, thereby increasing the additional modulation order eachreceiving end can obtain and data transmission rate. As noted above, inthe above non-orthogonal multi-user SM, such antennas multiplexing isalso a kind of multiplexing of channels. It should be noted that,according to these teachings, those skilled in the art can conceivevarious ways to multiplex the antennas or channels of the transmittingend. Accordingly, those skilled in the art can predetermine differentmapping rules to match with ways of multiplexing.

For example, in one embodiment, the antennas at the transmitting end canbe grouped such that each group of antennas can be multiplexed anddedicated to SM for multiple receiving ends. FIG. 6 is a schematicdiagram illustrating the example system for applying SM technology forpoint-to-multipoint transmission, which is a variation of the examplesystem shown in FIG. 3A. In the example system in FIG. 6, the antennasof the transmitting end 310 are grouped into two or more antenna sets(e.g., sets 330-1 and 330-2), and any antenna in each antenna set can bemultiplexed for any receiving end in a corresponding subset of receivingends. For example, the antenna set 330-1 can be multiplexed anddedicated to the SM for the receive ends 1 and 2, and the antenna set330-2 can be multiplexed and dedicated to the SM for the receive ends 3and 4, and the way of multiplexing the corresponding set of antennas foreach subset of receiving ends is similar to those described withreference to FIG. 3A. It should be noted that, in this embodiment, theimprovements on the additional modulation order obtained by eachreceiving end and the data transmission rate are less significant thanthe case where the antennas of the transmitting end are not grouped, butstill better than the case where each one antenna is dedicated to onereceiving end (i.e., the antennas are not multiplexed). In this case, itis necessary to determine in advance the mapping rules that matches withthe first antenna set 330-1 and the second antenna set 330-2. Themapping rules need to match with the number of antennas in the antennaset. For example, if there are 4 antennas in the first antenna set, themapping rule 800 in FIG. 8 can be used; if there are 8 antennas in thesecond antenna set, different mapping rules can be determined in advanceto specify the correspondence between three information bits in thefirst information flow and the 8 antennas. It is still necessary for themapping rules to specify different correspondences for multiplereceiving ends served by different antenna sets, to ensure that the samebit values for the multiple receiving ends served by the differentantenna sets can be mapped to antennas in the respective antenna sets.For example, for the receiving end 1 served by the first antenna set andthe receiving end 4 served by the second antenna set in FIG. 6, when thefirst portion of information bits for the two receiving ends are both“01”, these portions of information bits need to be mapped to theantennas in the first and second antenna sets, respectively.

In another embodiment, the antennas of the transmitting end can begrouped into two or more antenna sets with at least one antenna iscommon to the grouped antenna sets (i.e., the antenna sets can at leastpartly be overlapped), and each antenna set can be dedicated to the SMfor one or more receiving ends. In other words, any antenna in eachantenna set can be multiplexed for any receiving end in a correspondingset of receiving ends. FIG. 7 is a schematic diagram of the examplesystem for applying the SM technology for point-to-multipointtransmission, according to the embodiments herein. In this example,based on a predetermined mapping rule (e.g., the mapping rule 800), thefirst portion of information bits for the first receiving endcommunication device (e.g., the receiving end 1) are mapped to a firstantenna in the first antenna set (e.g., the first antenna set 330-1),and the first portion of information bits for the second receiving endcommunication device (e.g., the receiving end 4) are mapped to a secondantenna in the second antenna set (e.g., the second antenna set 330-2),wherein there is at least one common antenna (e.g., at least one ofantennas n1 to n2) in the first set of antennas and the second set ofantennas. A first transmission power is allocated to the first receivingend communication device (e.g., the receiving end 1), and a secondtransmission power is allocated to the second receiving endcommunication device (e.g., the receiving terminal 2). The secondportion of information bits for the first receiving end communicationdevice (e.g., the receiving end 1) is transmitted by the first antennaat the first transmission power, and the second portion of informationbits for the second receiving end communication device (e.g., thereceiving end 2) is transmitted by the second antenna at the secondtransmission power. In this example, there is a specific information bitvalue, such that the first antenna and the second antenna are the sameantenna (i.e., at least one of the antennas n1 to n2) if both the firstportion of information bits for the first receiving end communicationdevice (e.g., the receiving end 1) and the first portion of informationbits for the second receiving end communication device (e.g., thereceiving end 2) are equal to the specific information bit value.

In one implementation, there can be at least one antenna that is notcommon to the first set of antennas and the second set of antennas. Inanother implementation, the first antenna set and the second antenna setcan be a same antenna set, which is actually correspond to the examplesystem in FIG. 3A.

It should be noted that, in this embodiment, similarly to the above, itis necessary to determine in advance the mapping rules that matches withthe first antenna set 330-1 and the second antenna set 330-2. Similarly,the mapping rules need to match with the number of antennas in theantenna sets. It is still necessary for the mapping rules to specifycorrespondences for the multiple receiving ends served by differentantenna sets, to ensure that the same bit values for the multiplereceiving ends served by different antenna sets can be mapped toantennas in the respective antenna sets. In an implementation, there isa specific information bit value, such that the mapped first antenna andsecond antenna are the same antenna common to two antenna sets if boththe information bits in the first information flow for the receiving end1 and the information bits in the first information flow for thereceiving end 2 are equal to the specific information bit value.

Even if the first antenna set applies a first mapping rule and thesecond antenna set applies a second mapping rule different from thefirst one, the first information flows which are the same can still bemapped to an antenna belonging to both the first antenna set and thesecond antenna set. For example, for the first antenna set, the firstinformation flow “01” for a receiving end is mapped to the antenna, andfor the second antenna set, the first information flow “01” for areceiving end is mapped to the antenna. In this case, demodulation rulescan be the same for any receivers.

However, for different receivers (in other words, for different antennasets), the first information flows which are different can be mapped toan antenna belonging to both the first antenna set and the secondantenna set antennas. For example, for the first antenna set, the firstinformation flow “01” for one receiving end is mapped to the antenna,and for the second antenna set, the first information flow “10” foranother receiving end is mapped to the antenna. In this case,demodulation rules can be different for different receiving ends. Forexample, the above one receiving end demodulates the sequence number ofthe antenna into bits 01, and the other receiving end demodulates thesequence number of the antenna into bits 10. It works as long as themapping rules at both the transmitting end and the receiving end areconsistent.

It should be noted that, the transmitting end and the receiving end inFIGS. 6-7 can be implemented by using the above transmitting endcommunication device 400 and the receiving end communication device 500,respectively. Although the mapping rules can be different, the mappingoperations, power allocation operations, and transmission controloperations are similar to those described with reference to FIGS. 3A and4A-5B.

An example of the operation of the transmitting end communication device400 and the receiving end communication device 500 where the technologyof the present disclosure is used will be described below in conjunctionwith the above description.

In this example, the transmitting end communication device 400 controlsto transmit orthogonal training sequences on respective channels for thereceiving end communication devices to determine channel stateinformation for each channel, thereby performing spatial modulation anddemodulation. By performing channel estimation through transmitting thetraining sequences (e.g., pilot signals in the LTE system), a channelmatrix H^((k)) from the transmitting end communication device 400 to thekth receiving end (i.e., the receiving end k) can be obtained as:

$\begin{matrix}{{H^{(k)} = \left\lbrack {h_{1}^{(k)}\mspace{14mu} h_{2}^{(k)}\mspace{14mu} \ldots \mspace{14mu} h_{N_{t}}^{(k)}} \right\rbrack},} & (1) \\{h_{j}^{(k)} = \left\lbrack {h_{1,j}^{(k)}\mspace{14mu} h_{2,j}^{(k)}\mspace{20mu} \ldots \mspace{14mu} h_{N_{r_{k},j}}^{(k)}} \right\rbrack^{T}} & (2)\end{matrix}$

wherein h_(i,j) ^((k)) denotes the antenna gain the jth antenna at thetransmitting end to the ith antenna in the N_(r) _(k) antennas at thereceiving end k (where N_(r) _(k) ≥1), it is assumed that h_(i,j) ^((k))complies with the complex Gaussian independent identical distribution

(0, σ_(h) ²) for ease of analysis. Of course, those skilled in the artwill appreciate that h_(i,j) ^((k)) can alternatively comply with otherdistribution conditions different from the complex Gaussian independentdistribution

(0, σ_(h) ²).

At any time slice, at the transmitting end communication device 400, forany of the K receiving ends, such as the receiving end k, as in theabove step 401, the SM mapping unit 402 maps information bits in thefirst information flow for the receiving end to the correspondingantenna of the N_(t) antennas based on the predetermined mapping rule,to perform SM for the information bits. Further, as in the above step407, the transmitting end communication device 400 can further select acorresponding amplitude phase modulation according to channel stateinformation (e.g., CQI (Channel Quality Indicator)) that is feedback bythe receiving end (or measured from a reference signal from thereceiving end), and transmit the second portion of information bits forthe receiving end by using the selected corresponding amplitude phasemodulation. For example, in the example of FIG. 3A, information bits inthe second information flow for the receiving end are further mapped toparticular amplitude phase modulation symbols (i.e., constellationpoints in the constellation) in a particular amplitude phase modulationscheme, to perform the amplitude phase modulation for the informationbits. The total number of amplitude phase modulation symbols in theparticular amplitude phase modulation scheme (i.e., the total number ofconstellation points in the constellation) can be expressed as M_(k).The particular amplitude phase modulation scheme can depend on channelconditions, such as receiving SNR conditions at the receiving end, wherea higher receiving SNR can correspond to a higher order modulationscheme; and vice versa.

After mapping the information bits in the first information flow and thesecond information flow for the receiving end k to antennas andamplitude phase modulation symbols respectively, the followingtransmission signal vector is formed:

x_(j) _(k,) _(m) _(k) ^((k))=[0 . . . s_(m) _(k) . . . 0]^(T), wherein1≤j_(k)≤N_(t), 1≤m_(k)≤M_(k)  (3)

wherein j_(k) denotes the sequence number of the mapped antenna, andm_(k) denotes the sequence number of the mapped amplitude phasemodulation symbol in the M_(k) amplitude phase modulation symbols in thespecific amplitude phase modulation scheme. There are N_(t) elements inthe transmission signal vector corresponding to the N_(t) antennasrespectively, and s_(m) _(k) denotes the mapped amplitude phasemodulation symbol per se. The position of s_(m) _(k) in the abovetransmission signal vector corresponds to the mapped j_(k)th antenna. Inthis example, only the mapped antenna is used for signal transmission,and the powers at the other antennas are all zero. It can be seen thatin the case where the information bits in the first information flowsfor two or more receiving ends are the same, these information bits willbe mapped to a same antenna, thereby the information bits in the secondflows for these two or more receiving ends will be transmitted by thesame antenna.

For the receiving end k, the total SM symbols set considering theantenna mapping (or antenna selection) can be written as follows:

x^((k))={x_(j) _(k) _(,m) _(k) ^((k)):1≤j_(k)≤N_(t),1≤m_(k)≤M_(k)},  (4)

|x^((k))|=M_(k)N_(t)  (5)

wherein “|⋅|” denotes the number of elements in the set, and the meaningof equation (5) is there are M_(k)N_(t) elements in the above total SMsymbols set. It can be seen that the total modulation order of thereceiving end k is composed of two parts, that is, the traditionalamplitude phase modulation order and the additional modulation orderbrought by the SM, and the total modulation order can be written asfollows:

B _(k)=log₂(M _(k))+log₂(N _(t))  (6)

It can be seen that, compared to the example system in FIG. 2B whereantennas are grouped, the multi-user SM system (e.g., the system 300A)having the transmitting end communication device 400 according to theembodiments herein can achieve more improvement on the additionalmodulation order, and this improvement on the additional modulationorder is comparable to the additional modulation order in the point topoint SM system in FIG. 2A.

At the transmitting end communication device 400, as in the above step403, the power allocation unit 404 allocates transmission power to eachreceiving end, for example, allocates transmission power p_(k) to thereceiving end k, thereby forming a transmission power allocation result.For example, the transmission power allocation result can includeinformation indicating an absolute value or a relative value of thetransmission power allocated to each receiving end. In other examples,the transmission power allocation result can additionally oralternatively include information indicating an order of thetransmission power allocated to each receiving end or the demodulationorder. The power allocation unit 404 can further inform each receivingend of the transmission power allocation result.

It is worth noting here that it is necessary for the power allocationunit 404 to take into account demands of the SIC operations at thereceiving ends to allocate the transmission power. In the system of theembodiments herein, the transmitting end can transmit the transmissionsignals of multiple receiving ends in a superimposing manner on the sametime-frequency resources. Accordingly, each receiving end will need todetect transmission signals for other receiving ends by the SIC, and inturn detect and demodulate the transmission signals for the receivingend per se.

As an example, it is assumed that the transmitting end 310 cancommunicate with the receiving end 1 via a first physical communicationlink L1 and with the receiving end k via a second physical communicationlink Lk. It is assumed that the radio condition of the first physicalcommunication link L1 is poorer (e.g., because the receiving end 1 isfarther from the transmitting end 310) and the radio condition of thesecond physical communication link Lk is better (e.g., because thereceiving end k is closer to the transmitting end 310). This situationcan be temporary since the radio conditions are constantly changing. Inother words, for a particular radio transmission power, thesignal-to-interference-noise ratio SINR and carrier-to-interference C/Iratio at the receiving end 1 is lower (or much lower) than thecorresponding SINR and C/I ratio at the receiving end k. If the relativeradio conditions of the two receiving end 1 and the receiving end k areknown, the transmitting end 310 can proportionally allocate thetransmission power budget between the two receiving ends for aparticular time slice and a particular carrier frequency, such that afirst modulation symbol of the receiving end 1 (the receiving end underpoorer radio condition) is transmitted at higher transmission power thanthe power for transmitting a second modulation symbol of the receivingend k (the receiving end under better radio conditions).

Thus, given the current radio conditions and additional interferencecaused by transmitting the second modulation symbol to the receiving endk, the transmitting end 310 can allocate sufficient power fortransmitting the first modulation symbol of the receiving end 1,enabling the receiving end 1 to decode the first modulation symbol. Thetransmitting end 310 can then allocate less power for transmitting thesecond modulation symbol of the receiving end k, but the less power isstill sufficient for the receiving end k to cancel or reduce theinterference caused by the transmission of the first modulation symboland to decode the second modulation symbol. The transmitting end 310then transmits the two modulation symbols on the same time-frequencyresources, such that the two modulation symbols can be considered tocollide with each other. However, since the first modulation symbol istransmitted at the higher power than the power for transmitting thesecond modulation symbol, the second modulation symbol can just appearas noise or interference increasement for the receiving end 1. If thepower offset between transmitting the two modulation symbols issufficiently high, the degradation of the SINR or C/I ratio at thereceiving end 1 can be small or even insignificant.

Therefore, if the first modulation symbol is transmitted with asufficiently high power with respect to the transmission rate of thefirst modulation symbol, the current radio conditions and the additionalinterference caused by the transmission of the second modulation symbol,the receiving end 1 should be able to demodulate the first modulationsymbol. Moreover, since the radio condition of the receiving end k isbetter, the receiving end k can receive the first modulation symbol at ahigher SINR or C/I ratio than the receiving end 1, so the receiving endk should also be able to demodulate the first modulation symbol (in oneexample, the receiving end k can be aware of the modulation scheme ofthe first modulation symbol). Once the receiving end k demodulates thefirst modulation symbol, the receiving end k can process it asinterference, and use interference cancellation techniques to cancel theinterference from the overall transmitted signals received duringreception of the first and second modulation symbols. The residualsignal obtained after cancelling the interference can represent thesecond modulation symbol combined with noise and interference from othersources. If the second modulation symbol is transmitted with asufficiently high power (but lower than the power used to transmit thefirst modulation symbol) with respect to the transmission rate of thesecond modulation symbol and the radio conditions of the receivingterminal k, the receiving end k should be able to demodulate the secondmodulation symbol.

It should be understood that the above interference cancellation processcan be extended to more receiving ends, for example more than threereceiving ends. In particular, the highest power can be allocated fortransmission to a receiving end under the worst radio condition, thelowest power can be allocated for transmission to a receiving end underthe best radio condition, and the intermediate power can be allocatedfor transmission to a receiving end under the intermediate radiocondition. The receiving end under the best radio condition can thendemodulate the modulation symbols intended for the receiving end underthe worst radio condition and cancel the interference of the demodulatedsymbols from the received signal, then demodulate the modulation symbolsintended for the receiving end under the intermediate radio conditionand cancel the interference of the demodulated symbol, and finallydemodulate the modulation symbols intended for itself, thisdemodulating/cancelling process can be referred to as serialinterference cancellation (SIC). Likewise, the receiving end under theintermediate radio condition can demodulate the modulation symbolintended for the receiving end under the worst radio condition, cancelinterference of the demodulated symbol from the received signal, andthen demodulate the modulation symbol intended for itself. The receivingend under the worst radio condition can directly demodulate themodulation symbols intended for itself, since this modulation symbol istransmitted at the highest power. It will be appreciated that thoseskilled in the art will be able to extend the SIC techniques to four ormore receivers without the need for additional testing or furtherinventive work. It should also be understood that the order of thetransmission power allocated to a particular receiving end cancorrespond to the demodulation order of the receiving end in performingthe SIC. In general, the demodulation order of the receiving end towhich a higher transmission power is allocated can be in front relativeto other receiving ends.

In this example, the power allocation unit 404 allocating the firsttransmission power to the first receiving end communication device andthe second transmission power to the second receiving end communicationdevice can include calculating the transmission power allocation resultaccording to the transmission power allocation principle. It will beapparent to those skilled in the art that such transmission powerallocation is to ensure the receiving ends to perform the SIC. Asdescribed above, the transmission power allocation principle can includeone or more of the following: allocating a lower transmission power to areceiving end communication device closer to the transmitting end;allocating a lower transmission power to a receiving end communicationdevice with higher receiving SNR; allocating a higher transmission powerto a receiving end communication device with a higher data rate demand;and causing the receiving SNRs of all receiving end communicationdevices to be at the same level. These transmission power allocationprinciples are described below in detail.

Receiving SNR Principle

The receiving end feeds back the receiving SNR information to thetransmitting end, the transmitting end allocates more power to the userwith lower receiving SNR, and allocates less power to the user withhigher receiving SNR. In this way, the receiving end with lowerreceiving SNR can realize data demodulation by a smaller number of SICoperations, and the receiving end with higher receiving SNR can cancelinterference of other receiving ends by the SIC operation, demodulatedata of its own. This principle is the same as the power allocationprinciple described in the above embodiments.

Distance Principle

The distance principle is to allocate lower transmission power to thereceiving end communication device closer to the transmitting end andhigher transmission power to the receiving end communication devicefarther from the transmitting end. In general, when conditions such asinterference or the like are substantially the same, the larger thedistance from the receiving end to the transmitting end is, the lowerthe receiving power at the receiving end is, and the lower the receivingSNR is; the smaller the distance from the receiving end to thetransmitting end is, the higher the receiving power at the receiving endis, and the higher the receiving SNR is. Therefore, the distance fromthe receiving end to the transmitting end can be regarded as anindicator that can reflect the receiving SNR at the receiving end. Ifthe distance information is known, the distance principle can be used asan additional or alternative principle to the principle of receivingSNR.

Data Rate Requirement Principle

The receiving end can first feed back the data transmission requirementto the transmitting end, and the transmitting end can perform powerallocation to multiple receiving ends according to factors such asrequirement and priority level of the receiving end. For example, for areceiving end that requires a higher data transmission rate, thetransmitting end can allocate more power to support a higher phaseamplitude modulation order to increase the data transmission rate.

Fairness Principle

The receiving end can first feed back the receiving SNR to the receivingend, and the receiving end can make the final receiving SNR of themultiple receiving ends tend to be equal by performing power allocation,thereby realizing the principle of service fairness between the multiplereceiving ends.

The embodiments are not limited by the power allocation principle, andthose skilled in the art can formulate other power allocation principlesaccording to specific target requirements, and the correspondingsolutions still fall within the scope of the disclosure.

It should be understood that power allocation, for multiple receivingends according to different power allocation principles, is actually tosolve an optimization problem with different objectives, such asminimizing the average bit error rates (BER) of all receiving ends,minimizing the maximum BER of all receiving ends., making the receivingSINR of all receiving ends equal, and so on. This optimization problemcan be expressed as:

$\begin{matrix}{{\left\{ {p_{1},p_{2},\ldots \mspace{14mu},p_{K}} \right\} = {\underset{p_{1},p_{2},\ldots \mspace{14mu},p_{K}}{argmin}{f\left( {p_{1},p_{2},\ldots \mspace{14mu},p_{k}} \right)}}},} & (7)\end{matrix}$

wherein f(⋅) denotes the objective function, arg min f(⋅) denotes thevalue of the variable (p₁, p₂, . . . p_(k)) that minimizes f(⋅). As analternative to directly solving this optimization problem, for example,a multi-grid search (MGS) can be used to obtain a numericallyapproximate optimal solution with relatively low complexity. Inparticular, the total power can be divided into N shares (e.g., averagedinto N shares), and the MGS traverses all possible allocation patterns.It can be seen that as the grid value 1/N decreases, the performance ofthe numerical solution can be improved, but at the same time thecomputational complexity is increased. For the simple case where K=2,N=10, the MGS method traverses p₁ from 1/N to (N−1)/N and traverses all(N−1) possible allocation patterns. Considering a descending order ofthe power, i.e. p₁>p₂, the searching load can be halved.

For a certain optimization objective, the MGS method can derive specificpower allocation values according to equation (7). However, as the gridvalue decreases or the number of receiving ends increases, thecomplexity of the MGS method will increase rapidly. The presentdisclosure also provides a low complexity and efficient power allocationmethod, which particularly takes into account phenomenon that whencalculating an average BER of all K receiving ends, the BER is mainlyfrom the receiving end with the lowest receiving SINR (i.e., thereceiving end with the lowest receiving SINR may become the bottleneck),thus set an optimization target of making the receiving SINRs of allreceiving ends equal. Under the constraint of the total amount of powerat the transmitting end, the method calculates the power to be allocatedto each receiving end by making the receiving SINRs of all receivingends equal.

The above method expresses the receiving SINR at each receiving end as afunction of the power to be allocated, makes the receiving SINRs equal,and solves the equation for the power to be allocated to each receivingend under the constraint of the total power amount at the transmittingend. An example process of the method can be as follows.

When calculating the average BER for all K receiving ends, the BER ismainly from the receiving end with the lowest receiving SINR. At thereceiving end k, the receiving SINR after performing the SIC can beexpressed as:

$\begin{matrix}\begin{matrix}{{SINR}_{k} \approx \frac{{{\sqrt{p_{k}}h_{j_{k}}^{(k)}s_{m_{k}}}}_{F}^{2}}{{\sum_{l = {k + 1}}^{K}{{\sqrt{p_{l}}h_{j_{l}}^{(1)}s_{m_{l}}}}_{F}^{2}} + {\sigma_{n}^{2}N_{r}}}} \\{\approx \frac{p_{k}}{{\sum_{l = {k + 1}}^{K}p_{l}} + \sigma_{n}^{2}}}\end{matrix} & (8)\end{matrix}$

Wherein the number of receiving antennas at the receiving end k isN_(r), and the noise vector is denoted as n_(k)˜

(0, σ_(k) ²). The “≈” in the first line of formula (8) is inconsideration that the signals for the receiving ends ranking in frontmay not be cancelled completely. Considering the optimization objectiveof making the receiving SINRs of all receiving ends equal, the followingresults are obtained:

$\begin{matrix}{\frac{p_{1}}{{\sum_{l = 2}^{K}p_{l}} + \sigma_{n}^{2}} = {\frac{p_{2}}{{\sum_{l = 3}^{K}p_{l}} + \sigma_{n}^{2}} = {\ldots = \frac{p_{K}}{\sigma_{n}^{2}}}}} & (9)\end{matrix}$

Then, the power p_(k) allocated to the receiving end k can be expressedas:

$\begin{matrix}{p_{k} = {p_{k + 1}\frac{{\sum_{l = {k + 1}}^{K}p_{l}} + \sigma_{n}^{2}}{{\sum_{l = {k + 2}}^{K}p_{l}} + \sigma_{n}^{2}}}} & (10)\end{matrix}$

In a specific implementation, it can be assumed at first that p_(K)=α,and then p_((K-1)), p_((K-2)) until p₁ are sequentially calculatedaccording to the above formula. Thereafter, the value of thenormalization parameter α is determined by the power constraintcondition Σ_(k=1) ^(K)p_(k)=1. Finally, the specific power allocationvalues are obtained as follows:

$\begin{matrix}{p_{k} = \left\{ \begin{matrix}{\alpha,} & {k = K} \\{{p_{k + 1}\frac{{\sum_{l = {k + 1}}^{K}p_{l}} + \sigma_{n}^{2}}{{\sum_{l = {k + 2}}^{K}p_{l}} + \sigma_{n}^{2}}},} & {1 \leq k < K}\end{matrix} \right.} & (11)\end{matrix}$

Compared to the multi-dimensional grid search, this power allocationmethod with low complexity proposed here can directly calculate thepower allocation parameters. The performances of the two methods will becompared in the following simulation analysis.

It should be noted that the above power allocation process can calculatethe power allocation result in real time according to the states of thereceiving ends in the system, or can pre-calculate in the offline modeand store the power allocation result in a configuration table.Accordingly, in one embodiment, the transmission power allocation resultis pre-calculated according to a particular transmission powerallocation principle and stored for performing the transmission powerallocation; in another embodiment, the transmission power allocationresult is calculated in real time to perform transmission powerallocation. Therefore, the transmitting end can read power allocationparameters from the preset system information table, and/or can selectto adjust the power allocation in real time through user feedbackinformation, which depends on processing capability of the transmittingend. It can be seen that off-line computing can reduce computationalload at the transmitting end compared to real-time computing.

At the transmitting end communication device 400, as in the above step405, the transmission control unit 406 can control to transmit thesecond portion of information bits for each receiving end by the antennamapped by the SM mapping unit 402 at the transmission power allocated bythe power allocating unit 404.

In particular, in FIG. 3A, the transmission signal vectors of the Kreceiving ends are superimposed and transmitted by the mapped antenna,and the final total transmission signal can be written as:

x _(sum)=Σ_(k=1) ^(K)√{square root over (p _(k))}*x _(j) _(k) _(,m)_(k′) ^((k)), Σ_(k=1) ^(K) p _(k)=1  (12)

Heretofore, the operations of the transmitting end communication device400 in the examples where the technology herein is applied has beendescribed in detail. The corresponding operations of the receiving endcommunication device 500 in these examples will be described in detailbelow.

At the receiving end communication device 500, the detection unit 504can perform the SIC on the transmission signal received from thetransmitting end, to detect signals for other receiving endcommunication devices and cancel the signals as interference, until thesignal for the receiving end communication device 500 per se isdetected, wherein the signal for the receiving end communication device500 per se can include the modulation symbol for the communicationdevice and the sequence number of the antenna which transmitted thereceived transmission signal. Here, the sequence number of the antennacan be detected based on channel state information, wich information isdetermined by the receiving end communication device 500 based on thetraining sequences transmitted by the antenna. The detailed process ofSIC can be referred to the following description, for example, withrespect to FIGS. 9-10. Furthermore, the receiving end communicationdevice 500 can receive information indicating the order of thetransmission power used by the first antenna in transmitting the signalfor the receiving end per se among the transmission powers used intransmitting signals for all receiving end communication devices or theorder of demodulation, wherein the number of SIC performed depends onthe order or the order of demodulation.

The spatial demodulation mapping unit 502 can map the sequence number ofthe antenna which transmitted the received transmission signal to thefirst portion of information bits for the receiving end communicationdevice 500 per se based on the predetermined mapping rule (e.g., thepredetermined mapping rule 800 of the example shown in FIG. 8), and mapthe modulation symbols for the communication device to the secondportion of information bits for the receiving end according to therespective amplitude phase modulation method. Here, the first portion ofinformation bits can correspond to bit information in the firstinformation flow for the receiving end in FIGS. 3A-3C and FIGS. 6-7, andthe second portion of information bits can correspond to bit informationin the second information flow for the receiving end in FIGS. 3A-3C andFIGS. 6-7.

The process of the SIC according to embodiments herein will be describedbelow with reference to FIGS. 9-10.

It is assumed that at the kth receiving end k in FIG. 3A, thetransmission signal received from the transmitting end 310 can bewritten as follows:

y ^((k))=√{square root over (ρ_(k))}H ^((k))Σ_(l=1) ^(K)√{square rootover (p ₁)}*x _(j) _(l) _(,m) _(l) ^((l)) +n _(k)=√{square root over(ρ_(k))}Σ_(l=1) ^(K)√{square root over (p _(l))}*h _(j) _(l) ^((k)) s_(m) _(l) +n _(k)  (13)

wherein ρ_(k) denotes the receiver gain of the receiving end k, andn_(k)˜

(0, σ_(k) ²) ab denotes the noise vector, then the receiving SNR at thereceiving end k can be expressed as

${SNR}_{k} = {10\log_{10}{\frac{\rho_{k}}{\sigma_{k}^{2}}.}}$

According to the above idea of SIC, it is assumed that the transmittingend is transmitting to K receiving ends, i.e. the receiving end 1 to thereceiving end K, and for the receiving end k, it is necessary to firstdetect the signals for the receiving ends to which higher transmissionpowers is allocated than to per se and cancel them as interference, andthen its own signal is detected and demodulated. In one embodiment, thereceiving end detects signals for other receiving ends by usingdetection algorithms in the SIC, and the detection algorithm can includedetection algorithm, such as Maximum Likelihood (ML) or Maximum RatioCombining (MRC).

For convenience of description, it is assumed here that the transmissionpower allocation result is expressed as p₁>p₂> . . . >p_(K), that is,the amount of transmission power allocated is ranked in descending orderof the receiving end number. The following describes how to use the MLalgorithm and the MRC algorithm for signal detection and demodulation,respectively, with reference to the signal detection methods at thereceiving end shown in FIGS. 9 and 10.

ML Algorithm

FIG. 9 is a flow chart illustrating an exemplary method of performingsignal detection at a receiving end by using the ML algorithm, accordingto an embodiment herein. The ML algorithm is an optimal detectionalgorithm, and the detailed idea of the algorithm is as follows. For thereceiving end 1 with the highest allocated power, the sequence number ofthe antenna for the receiving end and the index of the amplitude phasemodulation symbol can be detected from the received signal y⁽¹⁾according to the following formula:

$\begin{matrix}\begin{matrix}{\left\lbrack {{\hat{j}}_{1,{ML}},{\hat{m}}_{1,{ML}}} \right\rbrack = {\underset{j_{1},m_{1}}{argmax}{p_{Y}\left( {\left. y^{(1)} \middle| x_{j_{1},m_{1}}^{(1)} \right.,H^{(1)}} \right)}}} \\{= {\underset{j_{1},m_{1}}{argmax}{{y^{(1)} - {\sqrt{\rho_{1}p_{1}}h_{j_{1}}^{(1)}s_{m_{1}}}}}_{F}^{2}}}\end{matrix} & (14)\end{matrix}$

wherein ĵ_(1,ML) denotes the sequence number of the antenna for thereceiving end, {circumflex over (m)}_(1,ML) denotes the index of theamplitude phase modulation symbol, and pΥ(y⁽¹⁾|x_(j) ₁ _(,m) _(1′)^((l))H⁽¹⁾) denotes the probability density function, ∥⋅∥_(F) denotesthe Frobenius norm. It can be understood that the processing of formula(14) is an exhaustive search for the combinations of the channel gainsfrom multiple antennas in the set of antennas at the transmitting end tothe receiving end and the modulation symbols in a particular modulationscheme, to find a combination of channel gain and modulation symbol thatbest approximates the received signal y⁽¹⁾. Next, bit information in thefirst information flow for the receiving end 1 can be determined basedon the above antenna sequence number according to the predeterminedmapping rule, and bit information in the second information flow for thereceiving end 1 can be determined based on the amplitude phasemodulation symbol.

For the receiving end k, it is necessary to detect signals for the first(k−1) receiving ends to which higher powers are allocated (i.e., thereceiving ends rank in front in the transmission power allocationresult) from the received signals based on the order of the receivingend in the transmission power allocation result, and to cancel thesignals as interference. In particular, the signal for the firstreceiving end 1 is detected from the received signal based on thefollowing formula:

$\begin{matrix}\begin{matrix}{\left\lbrack {{\hat{j}}_{1,k,{ML}},{\hat{m}}_{1,k,{ML}}} \right\rbrack = {\underset{j_{1},m_{1}}{argmax}{p_{Y}\left( {\left. y^{(k)} \middle| x_{j_{1},m_{1}}^{(1)} \right.,H^{(k)}} \right)}}} \\{= {\underset{j_{1},m_{1}}{argmax}{{y^{(k)} - {\sqrt{\rho_{k}p_{1}}h_{j_{1}}^{(k)}s_{m_{1}}}}}_{F}^{2}}}\end{matrix} & (15)\end{matrix}$

It can be understood that the processing in formula (15) is anexhaustive search for the combinations of the channel gains frommultiple antennas in the set of antennas at the transmitting end to thereceiving end and the modulation symbols in the particular modulationscheme, to find a combination of channel gain and modulation symbol thatbest approximates the received signal y^((k)).

It should be noted that [ĵ_(1,k,ML), {circumflex over (m)}_(1,k,ML)]here is obtained based on the signal y^((k)) received by the receivingend k, which is different from [ĵ_(1,ML), {circumflex over (m)}_(1,ML)]obtained based on the above signal y⁽¹⁾ received by the receiving end 1.Then, the interference caused by the receiving end 1 is cancelled fromthe received signal as follows:

y ₁ ^((k)) =y ^((k))−√{square root over (ρ_(k)p₁)}h _(ĵ) _(1,k,ML)^((k)) s _({circumflex over (m)}) _(1,k,ML)   (16)

Then, the signal for a second receiving end is detected from the updatedreceived signal based on the following formula:

$\begin{matrix}{\left\lbrack {{\hat{j}}_{2,k,{ML}},{\hat{m}}_{1,k,{ML}}} \right\rbrack = {\underset{j_{2},m_{2}}{argmax}{p_{Y}\left( {\left. y_{1}^{(k)} \middle| x_{j_{2},m_{2}}^{(2)} \right.,H^{(k)}} \right)}}} \\{= {\underset{j_{2},m_{2}}{argmax}{{y^{(k)} - {\sqrt{\rho_{k}p_{1}}h_{{\hat{j}}_{1,k,{ML}}}^{(k)}s_{{\hat{m}}_{1,k,{ML}}}} -}}}} \\{{\sqrt{\rho_{k}p_{2}}h_{j_{2}}^{(k)}s_{m_{2}}}}_{F}^{2}\end{matrix}$

Then, the received signal is updated again until the interference causedby the (k−1)th receiving end is cancelled, and the final updatedreceived signal is:

$\begin{matrix}{y_{k - 1}^{(k)} = {y^{(k)} - {\sqrt{\rho_{k}}{\sum\limits_{l = 1}^{k - 1}{\sqrt{p_{l}}h_{{\hat{j}}_{l,k,{ML}}}^{(k)}s_{{\hat{m}}_{l,k,{ML}}}}}}}} & (18)\end{matrix}$

Finally, the receiving end k detects the signal for itself according tothe following formula:

$\begin{matrix}{\left\lbrack {{\hat{j}}_{k,{ML}},{\hat{m}}_{k,{ML}}} \right\rbrack = {\underset{j_{k},m_{k}}{argmax}{p_{Y}\left( {\left. y_{k - 1}^{(k)} \middle| x_{j_{k},m_{k}}^{(k)} \right.,H^{(k)}} \right)}}} \\{= {\underset{j_{k},m_{k}}{argmax}{{y^{(k)} - {\sqrt{\rho_{k}}{\sum\limits_{l = 1}^{k - 1}{\sqrt{p_{l}}h_{{\hat{j}}_{l,k,{ML}}}^{(k)}s_{{\hat{m}}_{l,k,{ML}}}}}} -}}}} \\{{\sqrt{\rho_{k}p_{k}}h_{j_{k}}^{(k)}s_{m_{k}}}}_{F}^{2}\end{matrix}$

The bit information in the first information flow for the receiving endk can be determined based on the antenna sequence number according tothe predetermined mapping rule, and the bit information in the secondinformation flow for the receiving end k can be determined based on theamplitude phase modulation symbol. Since the ML algorithm requires anexhaustive search for the set of spatial modulation symbols as shown informula (4), the computational complexity is related to the product ofM_(k) and N_(t).

According to the above idea of the ML algorithm, the example method ofsignal detection at the receiving end in FIG. 9 operates as follows. Forthe received signal of any receiving end, make an initial value of Opequal to the order of the receiving end in the transmission powerallocation result or to the demodulation order, and at block 901, thesequence number of the antenna and the amplitude phase modulation symbolfor a receiving end to which the highest transmission power is allocatedin the received signal is simultaneously detected. Here, if the powerallocation is the highest in the transmission power allocation, theinitial value of Op is 1, and the initial value of Op is incremented asthe allocated transmission power is decremented. In one embodiment, thesequence number of the antenna can be detected based on correspondingchannel state information, which information is determined by thereceiving end communication device 500 based on the training sequencestransmitted by the corresponding antenna. At block 903, the value ofrank Op is decremented by one. At block 905, it is determined if thevalue of Op is zero. If the value of Op is 0, it indicates that there isno need to perform interference cancellation on the received signal orinterference cancellation has been completed for the received signal,the method proceeds to block 909; otherwise, it indicates there is stillneed to cancel interferences from the receiving end with highertransmission power allocation, and the method proceeds to the block 907.At block 907, the signal for the receiving end with the highesttransmission power allocated can be cancelled from the received signalas interference to obtain an updated received signal. Next, the methodreturns to block 901 where the operations of blocks 901-905 areperformed again for the updated received signal and the updated orderOp. At block 909, based on the sequence number of antenna most recentlydetected at block 901, bit information in the first information flow forthe receiving end is determined according to the predetermined mappingrule, and based on the modulation symbol most recently detected at block901, bit information in the second information flow for the receivingend is determined.

MRC Algorithm

FIG. 10 is a flow chart illustrating an exemplary method of signaldetection at the receiving end by using the MRC algorithm, according toan embodiment herein. The MRC algorithm is a sub-optimal detectionalgorithm that can replace the ML algorithm. In the MRC algorithm, it isnecessary to first detect the sequence number of antenna for thereceiving end, and then detect the amplitude phase modulation for thereceiving end with the sequence number of the antenna being known, whichis different from the ML algorithm where the sequence number of antennaand the amplitude phase modulation symbol for the receiving end aredetected at the same time. Taking cancellation of the signal for thefirst receiving end 1 as interference from the received signal at thereceiving end k as an example, for the receiving end k, firstly, anexhaustive search is done on the channel gains from the multipleantennas in set of antennas at the transmitting end to the receivingend, the sequence number of antenna for the first receiving end 1 isdetected from the received signal by using the following formula:

$\begin{matrix}{{\hat{j}}_{1,k,{MRC}} = {\arg \; {\max_{j_{1}}\frac{\left\lbrack h_{j_{1}}^{(k)} \right\rbrack^{H}y^{(k)}}{\sqrt{\rho_{k}p_{1}}{h_{j_{1}}^{(k)}}_{F}^{2}}}}} & (20)\end{matrix}$

Then, with the sequence number ĵ_(1,k,MRC) of the antenna being known,an exhaustive search is done on the modulation symbols in the particularmodulation scheme, and the amplitude phase modulation symbol for thefirst receiving end 1 is detected based on the following formula:

$\begin{matrix}{{\hat{m}}_{1,k,{MRC}} = {\arg \; {\min_{m_{1}}{{s_{m_{1}} - \frac{\left\lbrack h_{{\hat{j}}_{1,k,{MRC}}}^{(k)} \right\rbrack^{H}y^{(k)}}{\sqrt{\rho_{k}p_{1}}{h_{{\hat{j}}_{1,k,{MRC}}}^{(k)}}_{F}^{2}}}}}}} & (21)\end{matrix}$

In addition to the above differences, other processings of the MRCalgorithm is similar to that described with reference to the MLalgorithm and will not be repeated here. Since the MRC algorithm detectsseparately the sequence number of antenna and the amplitude phasemodulation symbol for the receiving end, the computational complexity isrelated to the sum of M_(k) and N_(t).

The method of signal detection at the receiving end according to theidea of the MRC algorithm is shown in FIG. 10. In the method of FIG. 9,the sequence number of antenna and the amplitude phase modulation symbolfor the receiving end are simultaneously detected at block 901. Incontrast, the method illustrated in FIG. 10 completes detection of thesequence number of antenna and the amplitude phase modulation symbol forthe receiving end with the highest transmission power allocated in thereceived signals at blocks 1001 a and 1001 b, respectively. Except forthe above differences, the other processings in FIG. 10 are similar tothose described with reference to FIG. 9, and will not be repeated here.

Of course, in other embodiments, those skilled in the art can also useother detection algorithms to perform the above-mentioned SIC, whichwill not be described in detail herein.

In order to further facilitate the understanding of the SM technologyherein, the signaling interaction process between the transmitting endand the receiving end will be described below with reference to FIG. 11in detail.

FIG. 11 shows a flow diagram of an example process of signalinginteraction for applying point-to-multipoint transmission using the SMtechnology. In particular, at step 1101, the transmitting end 310controls to transmit, by using the respective antennas on thecorresponding channels, orthogonal training sequences (such as pilotsignals) to the receiving end 1 to the receiving end K, for thereceiving end (e.g., the first receiving end communication device andthe second receiving end communication device) to determine channelstate information of each channel, thereby performing the spatialmodulation and demodulation. At step 1102, each receiving end performschannel estimation based on the received training sequences to determinechannel state information (e.g., SNR or C/I ratio) for each channel, andat step 1103 feeds back information to the transmitting end, includingchannel state information and traffic requirements, etc. Thetransmitting end 310 can determine radio conditions for each receivingend based on the feedback information, thereby performing theabove-mentioned transmission power allocation and determining theamplitude phase modulation scheme. In one embodiment, the transmittingend 310 can control to transmit orthogonal training sequences on therespective channels, for the receiving ends 1 to K to determine channelstate information for each channel, thereby performing spatialmodulation and demodulation. Accordingly, the receiving ends 1 to K candetect the sequence number of the antenna based on the channel stateinformation. In another embodiment, the transmitting end 310 can selecta corresponding amplitude phase modulation scheme according to thechannel state information of the receiving ends 1 to K, and transmitinformation bits in the second flow for the receiving ends 1 to K byusing the selected corresponding amplitude phase modulation scheme.Accordingly, the receiving ends 1 to K can receive information on theamplitude phase modulation scheme from the transmitting end 310, anddetermine information bits in the second information flow for thereceiving end itself by using the amplitude phase modulation schemeindicated by the information on the amplitude phase modulation scheme.

At step 1104, the transmitting end 310 transmits the spatial modulationconfiguration information to the receiving ends 1 to K, and the spatialmodulation configuration information can include, for example, thetransmission power allocation result and the amplitude phase modulationscheme information described above. In one embodiment, the transmissionpower allocation result can be just the order of the power allocated toeach receiving end or the demodulation order. At step 1105, thetransmitting end transmits the non-orthogonal spatial modulatedtransmission signal to the receiving ends 1 to K, and the transmissionsignal can be a final total transmission signal formed by superimposingthe transmission signal vectors for the respective receiving ends. At1106, each receiving end detects the sequence number of antenna and theamplitude phase modulation symbol by the SIC, and further determinesinformation bits for the receiving end. In an embodiment, the receivingends 1 to K can receive information indicating the order of thetransmission power used in transmitting the signal for the receiving enditself among the transmission powers used for transmitting signals forall receiving ends, wherein the number of times the SIC operationperforms can depend on the order. The process of SIC can be referred tothe above description, for example, with respect to FIGS. 9-10, and willnot be repeated here.

According to the non-orthogonal multi-user SM technology of the presentdisclosure, by multiplexing the antennas at the transmitting end toperform SM for multiple receiving ends at the same time, the additionalmodulation order obtained by each receiving end and the datatransmission rate are increased. From another perspective, thenon-orthogonal multi-user SM technology according to the presentdisclosure can improve the demodulation performance of the receiving endwhile maintaining the same data transmission rate. It should beunderstood that the above transmitting end communication device 400 andother implementations of the communication device 400 (e.g., basestations) can also have the ability to perform orthogonal spatialmodulation. The transmitting end communication device 400 candynamically determine whether to enable the non-orthogonal spatialmodulation according to the embodiment herein as desired, to obtain theabove performance improvement. For example, the non-orthogonal spatialmodulation is enabled only when data transmission resources are tight oruser traffic delay requirements are strict. Accordingly, thetransmitting end communication device 400 can include a switch unit, andcontrol whether or not to enable the non-orthogonal spatial modulationby the switch unit. In one embodiment, the transmitting endcommunication device 400 can further control to switch between theexample implementations shown in FIGS. 3A, 6-7 and other possiblealternatives by the switch unit.

The improvement of the performance of the communication system broughtby the technology of the present disclosure will be described below withreference to the performance simulation results shown in FIGS. 12A to12D.

The Monte Carlo random method is used here to perform a simulationexperiment. Through 10⁶ random channel simulations, the performancecurve of the average bit error rate (BER) relative to the receiving SNRof the receiving antenna is plotted. The specific idea is: firstly, theobjective function is set as making the average BER of multiplereceiving ends lowest, and an approximate optimal point in powerallocation between multiple receiving ends is obtained by using themulti-dimensional grid search (MGS); then the relationship between theaverage BER and the receiving SNR at the receiving end is plotted. Thesimulation parameters and simulation results are described in detailbelow with respect to two simulation scenarios.

Scenario With 2 Receiving Ends

For the scenario with two receiving ends, the number of receiving endsis K=2. The approximate optimal power allocation point is firstdetermined by grid search. The system parameters are set as follows: thenumber of antennas N_(t)=4, the number of receiving antennasN_(r1)=N_(r2)=8, the total spatial modulation order B₁=B₂=3, the numberof the amplitude phase modulation symbols M₁=M₂=2 (i.e., BPSK). Thepower allocation is performed with the objective of making the averageBER of the two receiving ends lowest. It is assumed that the receivingSNRs of the receiving ends are the same, that is, SNR₁=SNR₂. Since thereceiving SNRs of the two receiving ends are equal, it is assumed thatthe power allocated to the receiving end 1 is greater than the powerallocated to the receiving end 2, that is, p₁>p₂, p₁+p₂=1. By dividingthe interval p₁∈[0.5,1] into 25 sampling points, considering the casesof three different receiving SNRs, that is,

${{10\log_{10}\frac{\rho_{k}}{\sigma_{k}^{2}}} = 5},{10},{15\mspace{14mu} {dB}},$

grid search is performed for performance of various power allocations.The simulation results are shown in FIG. 12A, and the straight dashedline gives an approximate optimal power allocation configuration. Thispower allocation information can be calculated in real time, or can bepre-calculated in an offline mode and stored in the configuration table.

Next, based on the approximate optimal power configuration, the BERperformances of the existing non-orthogonal SM scheme (e.g. FIG. 2B) andthe orthogonal SM scheme of the present disclosure are compared underdifferent receiving SNRs. The system parameters are set as follows:B₁=B₂=3, 4, N_(t)=4, K=2, N_(r1)=N_(r2)=8, M₁=M₂=2, 4 (i.e., BPSK andQPSK, corresponding to B₁=B₂=3, 4). In the existing scheme, 4 antennasare divided into 2 groups for spatial modulation for 2 receiving ends,that is, only 1 bit is used for spatial modulation for each receivingend, and in order to provide three-order modulation, QPSK is requiredfor the amplitude phase modulation. For the non-orthogonal spatialmodulation scheme, 4 antennas can all be used for spatial modulation foreach receiving end, that is, 2 bits are used for spatial modulation foreach receiving end, accordingly it just requires BPSK for the phaseamplitude modulation can the three-order modulation be provided. As canbe seen in FIG. 12B, under the three-order modulation, when thereceiving SNR is lower, the BER performance of the scheme herein issimilar to that of the existing solution; as the receiving SNRincreases, the BER of the scheme herein gets much lower than that of theexisting solution. Under the four-order modulation, a similarimprovement in BER performance can be seen. It can be seen that thesolution of the present disclosure can obtain significant beneficialtechnical effects especially in the case of a higher SNR.

Scenario with 4 Receiving Ends

For the scenario with four receivers, the number of receiving ends isK=4. The parameters used to determine the approximate optimal powerallocation point by grid search are as follows: N_(t)=8,N_(r1)=N_(r2)=16, B₁=B₂=4, M₁=M₂=2 (i.e. BPSK). The power allocation isperformed with an objective of making the average BERs of the fourreceiving ends lowest. It is assumed that the receiving SNRs at thereceiving ends are the same. The search load for the approximate optimalsolution of power allocation to the four receiving ends is greater,assumption is thus made about the powers between the receiving ends,that is, p₂=(1−p₁)*p₁, p₃=(1−p₁−p₂)*p₁, p₄=1−p₁−p₂−p₃, Σp_(k)=1. Bydividing the interval p₁∈[0.5,1] into 25 sampling points, consideringthree cases of different receiving SNRs, i.e.

${{10\log_{10}\frac{\rho_{k}}{\sigma_{k}^{2}}} = 5},{10},{15\mspace{14mu} {dB}},$

grid search is performed for performance of various power allocations.The simulation results are shown in FIG. 12C, and the straight dashedline gives an approximate optimal power allocation configuration.

Next, based on the approximate optimal power configuration, the BERperformances of the existing non-orthogonal SM scheme (e.g. FIG. 2B) andthe orthogonal SM scheme of the present disclosure are compared underdifferent receiving SNRs. The system parameters are set as follows:B₁=B₂=4, 5, 6, N_(t)=8, K=4, N_(r1)=N_(r2)=16, M₁=M₂=2, 4, 8 (i.e.,BPSK, QPSK and 8PSK). As can be seen in FIG. 12B, under the four-ordermodulation, when the receiving SNR is lower, the BER performance of thescheme herein is similar to that of the existing solution; as thereceiving SNR increases, the BER of the scheme herein gets much lowerthan that of the existing solution. Under the five-order or six-ordermodulation, a similar improvement in BER performance can be seen. It canbe seen that the solution of the present disclosure can obtainsignificant beneficial technical effects especially in the case of ahigher SNR.

The performances of the low complexity power allocation andmulti-dimensional grid search power allocation method according to thepresent disclosure will be compared and analyzed with reference to thesimulation results shown in FIG. 12E.

The Monte Carlo random method is again used here to perform a simulationexperiment. Through 10⁶ random channel simulations, the performancecurve of the average bit error rate (BER) relative to the receiving SNRof the receiving antenna is plotted.

The simulation scenarios and parameters in this example are consistentwith the scenarios and parameters of the above scenario with tworeceiving ends. For the multi-dimensional grid search method, theinterval p₁∈[0.5,1] is divided into 100 sampling points, and the averageBER result is simulated for each sampling point. Among the 100 samplingpoints, the power allocation value corresponding to the sampling pointwith the lowest average BER is selected as the final result of the gridsearch. Under the power allocation values obtained by the grid search,the BER performances of the non-orthogonal spatial modulation using theML and MRC detection algorithms are shown as the two dashed lines inFIG. 12E, respectively. For the low complexity power allocation method,the allocated power value can be directly calculated by formula (11).Under this power value, the BER performances of the non-orthogonalspatial modulation using the ML and MRC detection algorithms are shownby the two solid lines in FIG. 12E, respectively. As shown in FIG. 12E,under the MRC detection algorithm, the performance of the low complexitypower allocation method can approach the performance of themulti-dimensional grid search method. Under the ML detection algorithm,when the receiving SNR is lower, there is a performance gap between thelow complexity power allocation method and the multi-dimensional gridsearch method; however, as the receiving SNR is gradually increased, thegap can be gradually reduced. It can be seen that in most cases, the lowcomplexity power allocation method according to the present disclosurecan be used instead of the multi-dimensional grid search method.

It should be understood that machine-executable instructions in storagemedium and program products according to the embodiments herein can alsobe configured to perform the methods corresponding to the deviceembodiments described above, thus contents not described in detailherein can be referred to the corresponding descriptions above, whichdescriptions are not repeated herein.

Accordingly, the storage medium for storing the above program productsand machine executable instructions also falls into scope of the presentinvention. The storage medium includes, but is not limited to, a floppydisk, an optical disk, a magneto-optical disk, a memory card, a memorystick, and the like.

In addition, it should be noted that the above processes and devices canalso be implemented by software and/or firmware. In the case of beingimplemented by software and/or firmware, a program constituting thesoftware is installed from a storage medium or a network to a computerwith a dedicated hardware structure, such as the general-purposepersonal computer 1300 shown in FIG. 13, which, when is installed withvarious programs, can execute various functions and so on. FIG. 13 is ablock diagram illustrating an example structure of a personal computerwhich can be employed as an information processing device in theembodiment herein.

In FIG. 13, a central processing unit (CPU) 1301 executes variousprocesses in accordance with a program stored in a read-only memory(ROM) 1302 or a program loaded from a storage section 1308 to a randomaccess memory (RAM) 1303. In the RAM 1303, data required when the CPU1301 executes various processes and the like is also stored as needed.

The CPU 1301, the ROM 1302, and the RAM 1303 are connected to each othervia a bus 1304. An input/output interface 1305 is also connected to bus1304.

The following components are connected to the input/output interface1305: an input section 1306 including a keyboard, a mouse, etc.; anoutput section 1307 including a display such as a cathode ray tube(CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; thestorage section 1308 including a hard disk etc.; and a communicationsection 1309 including a network interface card such as a LAN card, amodem, etc.. The communication section 1309 performs communicationprocessing via a network such as the Internet.

A driver 1310 is also connected to the input/output interface 1305 asneeded. A removable medium 1311 such as a magnetic disk, an opticaldisk, a magneto-optical disk, a semiconductor memory or the like ismounted on the drive 1310 as needed, so that the computer program readtherefrom is installed into the storage section 1308 as needed.

In the case where the above processings are implemented by software, aprogram constituting the software is installed from a network such asthe Internet or a storage medium such as the removable medium 1311.

It should be understood by those skilled in the art that the storagemedium is not limited to the removable medium 1311 shown in FIG. 13 inwhich the program is stored and which is distributed separately from thedevice to provide the program to users. Examples of the removable medium1311 include a magnetic disk (including a floppy disk (registeredtrademark)), an optical disk (including a compact disk read only memory(CD-ROM) and a digital versatile disk (DVD)), a magneto-optical disk(including a mini disk (MD) (registered trademark)) and a semiconductormemory. Alternatively, the storage medium can be a ROM 1302, a hard diskincluded in the storage section 1308, or the like, in which programs arestored and which is distributed to users together with the devicecontaining it.

The technology of the present disclosure can be applied to variousproducts. For example, the base stations mentioned herein can beimplemented as any type of evolved Node B (eNB), such as a macro eNB anda small eNB. The small eNB can be an eNB covering a cell smaller thanthe macro cell, such as a pico eNB, a micro eNB, and a home (femto) eNB.Alternatively, the base station can be implemented as any other type ofbase station, such as a NodeB and a Base Transceiver Station (BTS). Thebase station can include: a body (also referred to as a base stationdevice) configured to control radio communication; and one or moreremote radio heads (RRHs) disposed at different locations from the body.In addition, various types of terminals which will be described belowcan each operate as a base station by performing base station functionstemporarily or semi-persistently.

For example, the user device mentioned herein can be implemented as amobile terminal (such as a smartphone, a tablet personal computer (PC),a notebook PC, a portable game terminal, a portable/dongle type mobilerouter and digital camera) or in-vehicle terminal (such as a carnavigation device). The user device can also be implemented as aterminal that performs machine-to-machine (M2M) communication (alsoreferred to as a machine type communication (MTC) terminal). Further,the user device can be a radio communication module (such as anintegrated circuit module including a single wafer) installed on each ofthe above terminals.

Application examples according to the present disclosure will bedescribed below with reference to FIGS. 14 to 17.

Application Example for Base Stations First Application Example

FIG. 14 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology herein can be applied.The eNB 1400 includes multiple antennas 1410 and a base station device1420. The base station device 1420 and each antenna 1410 can beconnected to each other via an RF cable. In one implementation, the eNB1400 (or base station device 1420) herein can correspond to thetransmitting end communication device 400 described above. In anotherimplementation, the eNB 1400 (or base station device 1420) cancorrespond to the receiving end communication device 500 describedabove.

Each of the antennas 1410 includes a single or multiple antenna elements(such as the multiple antenna elements included in a Multiple Input andMultiple Output (MIMO) antenna), and is used for the base station device1420 to transmit and receive radio signals. As shown in FIG. 14, the eNB1400 can include multiple antennas 1410. For example, the multipleantennas 1410 can be compatible with multiple frequency bands used bythe eNB 1400.

The base station device 1420 includes a controller 1421, a memory 1422,a network interface 1423, and a radio communication interface 1425.

The controller 1421 can be, for example, a CPU or a DSP, and operatesvarious functions of higher layers of the base station device 1420. Forexample, controller 1421 generates data packets from data in signalsprocessed by the radio communication interface 1425, and transfers thegenerated packets via the network interface 1423. The controller 1421can bundle data from multiple baseband processors to generate bundledpackets, and transfer the generated bundled packets. The controller 1421can have logic functions for performing control such as radio resourcecontrol, radio bearer control, mobility management, admission control,and scheduling. These controls can be performed in corporation with aneNB nearby or a core network node. The memory 1422 includes RAM and ROM,and stores a program that is executed by the controller 1421 and varioustypes of control data such as a terminal list, transmission power data,and scheduling data.

The network interface 1423 is a communication interface for connectingthe base station device 1420 to the core network 1424. The controller1421 can communicate with the core network node or another eNB via thenetwork interface 1423. In this case, the eNB 1400 and the core networknode or the other eNB can be connected to each other through a logicalinterface such as an S1 interface and an X2 interface. The networkinterface 1423 can also be a wired communication interface or a radiocommunication interface for radio backhaul lines. If the networkinterface 1423 is a radio communication interface, the network interface1423 can use a higher frequency band for radio communication than afrequency band used by the radio communication interface 1425.

The radio communication interface 1425 supports any cellularcommunication schemes, such as Long Term Evolution (LTE) andLTE-Advanced, and provides radio connection to a terminal positioned ina cell of the eNB 1400 via the antenna 1410. The radio communicationinterface 1425 can typically include, for example, a baseband (BB)processor 1426 and a RF circuit 1427. The BB processor 1426 can perform,for example, encoding/decoding, modulation/demodulation, andmultiplexing/demultiplexing, and performs various types of signalprocessing of layers such as L1, Medium Access Control (MAC), Radio LinkControl (RLC), and Packet Data Convergence Protocol (PDCP). Instead ofthe controller 1421, the BB processor 1426 can have a part or all of theabove-described logical functions. The BB processor 1426 can be a memorythat stores a communication control program, or a module that includes aprocessor configured to execute the program and a related circuit.Updating the program can change the functions of the BB processor 1426.The module can be a card or a blade that is inserted into a slot of thebase station device 1420. Alternatively, the module can be a chip thatis mounted on the card or the blade. Meanwhile, the RF circuit 1427 caninclude, for example, a mixer, a filter, and an amplifier, and transmitsand receives radio signals via the antenna 1410. Although FIG. 14illustrates an example in which one RF circuit 1427 is connected to oneantenna 1410, the present disclosure is not limited to thereto; rather,one RF circuit 1427 can connect to a plurality of antennas 1410 at thesame time.

As illustrated in FIG. 14, the radio communication interface 1425 caninclude multiple BB processors 1426. For example, the multiple BBprocessors 1426 can be compatible with multiple frequency bands used bythe eNB 1400. As illustrated in FIG. 14, the radio communicationinterface 1425 can include the multiple RF circuits 1427. For example,the multiple RF circuits 1427 can be compatible with multiple antennaelements. Although FIG. 14 illustrates the example in which the radiocommunication interface 1425 includes the multiple BB processors 1426and the multiple RF circuits 1427, the radio communication interface1425 can also include a single BB processor 1426 or a single RF circuit1427.

Second Application Example

FIG. 15 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology herein can be applied.The eNB 1530 includes multiple antennas 1540, a base station device1550, and an RRH 1560. The RRH 1560 and each antenna 1540 can beconnected to each other via an RF cable. The base station device 1550and the RRH 1560 can be connected to each other via a high speed linesuch as a fiber optic cable. In one implementation, the eNB 1530 (orbase station device 1550) herein can correspond to the transmitting endcommunication device 400 described above. In another implementation, theeNB 1530 (or base station device 1550) can correspond to the receivingend communication device 500 described above.

Each of the antennas 1540 includes a single or multiple antenna elementssuch as multiple antenna elements included in a MIMO antenna and is usedfor the RRH 1560 to transmit and receive radio signals. The eNB 1530 caninclude the multiple antennas 1540, as illustrated in FIG. 15. Forexample, the multiple antennas 1540 can be compatible with multiplefrequency bands used by the eNB 1530.

The base station device 1550 includes a controller 1551, a memory 1552,a network interface 1553, a radio communication interface 1555, and aconnection interface 1557. The controller 1551, the memory 1552, and thenetwork interface 1553 are the same as the controller 1421, the memory1422, and the network interface 1423 described with reference to FIG.14.

The radio communication interface 1555 supports any cellularcommunication scheme (such as LTE and LTE-Advanced) and provides radiocommunication to terminals positioned in a sector corresponding to theRRH 1560 via the RRH 1560 and the antenna 1540. The radio communicationinterface 1555 can typically include, for example, a BB processor 1556.The BB processor 1556 is the same as the BB processor 1426 describedwith reference to FIG. 14, except that the BB processor 1556 isconnected to the RF circuit 1564 of the RRH 1560 via the connectioninterface 1557. The radio communication interface 1555 can include themultiple BB processors 1556, as illustrated in FIG. 15. For example, themultiple BB processors 1556 can be compatible with multiple frequencybands used by the eNB 1530. Although FIG. 15 illustrates the example inwhich the radio communication interface 1555 includes the multiple BBprocessors 1556, the radio communication interface 1555 can also includea single BB processor 1556.

The connection interface 1557 is an interface for connecting the basestation device 1550 (the radio communication interface 1555) to the RRH1560. The connection interface 1557 can also be a communication modulefor communication in the above-described high speed line that connectsthe base station device 1550 (the radio communication interface 1555) tothe RRH 1560.

The RRH 1560 includes a connection interface 1561 and a radiocommunication interface 1563.

The connection interface 1561 is an interface for connecting the RRH1560 (the radio communication interface 1563) to the base station device1550. The connection interface 1561 can also be a communication modulefor communication in the above-described high speed line.

The radio communication interface 1563 transmits and receives radiosignals via the antenna 1540. The radio communication interface 1563 cantypically include, for example, the RF circuitry 1564. The RF circuit1564 can include, for example, a mixer, a filter, and an amplifier, andtransmits and receives radio signals via the antenna 1540. Although FIG.15 illustrates the example in which one RF circuit 1564 is connected toone antenna 1540, the present disclosure is not limited to thereto;rather, one RF circuit 1564 can connect to multiple antennas 1540 at thesame time.

The radio communication interface 1563 can include multiple RF circuits1564, as illustrated in FIG. 15. For example, the multiple RF circuits1564 can support multiple antenna elements. Although FIG. 15 illustratesthe example in which the radio communication interface 1563 includes themultiple RF circuits 1564, the radio communication interface 1563 canalso include a single RF circuit 1564.

Applications Examples for user Devices First Application Example

FIG. 16 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 1600 to which the technology herein can beapplied. The smartphone 1600 includes a processor 1601, a memory 1602, astorage 1603, an external connection interface 1604, an camera 1606, asensor 1607, a microphone 1608, an input device 1609, a display device1610, a speaker 1611, a radio communication interface 1612, one or moreantenna switch 1615, one or more antennas 1616, a bus 1617, a battery1618, and an auxiliary controller 1619. In one implementation, thesmartphone 1600 (or the processor 1601) herein can correspond to thetransmitting end communication device 400 described above. In anotherimplementation, the smartphone 1600 (or the processor 1601) herein cancorrespond to the receiving end communication device 500 describedabove.

The processor 1601 can be, for example, a CPU or a system on chip (SoC),and controls functions of an application layer and the other layers ofthe smartphone 1600. The memory 1602 includes RAM and ROM, and stores aprogram that is executed by the processor 1601, and data. The storage1603 can include a storage medium such as a semiconductor memory and ahard disk. The external connection interface 1604 is an interface forconnecting an external device such as a memory card and a universalserial bus (USB) device to the smartphone 1600.

The camera 1606 includes an image sensor such as a charge coupled device(CCD) and a complementary metal oxide semiconductor (CMOS), andgenerates a captured image. Sensor 1607 can include a group of sensorssuch as a measurement sensor, a gyro sensor, a geomagnetic sensor, andan acceleration sensor. The microphone 1608 converts the sounds that areinput to the smartphone 1600 to audio signals. The input device 1609includes, for example, a touch sensor configured to detect touch on ascreen of the display device 1610, a keypad, a keyboard, a button, or aswitch, and receives an operation or an information input from a user.The display device 1610 includes a screen such as a liquid crystaldisplay (LCD) and an organic light emitting diode (OLED) display, anddisplays an output image of the smartphone 1600. The speaker 1611converts audio signals that are output from the smartphone 1600 tosounds.

The radio communication interface 1612 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs radiocommunication. The radio communication interface 1612 can typicallyinclude, for example, a BB processor 1613 and an RF circuitry 1614. TheBB processor 1613 can perform, for example, encoding/decoding,modulation/demodulation, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 1614 can include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna1616. The radio communication interface 1612 can be a one chip modulethat integrates the BB processor 1613 and the RF circuit 1614 thereon.The radio communication interface 1612 can include multiple BBprocessors 1613 and multiple RF circuits 1614, as illustrated in FIG.16. Although FIG. 16 illustrates the example in which the radiocommunication interface 1612 includes the multiple BB processors 1613and multiple RF circuits 1614, the radio communication interface 1612can also include a single BB processor 1613 or a single RF circuit 1614.

Furthermore, in addition to the cellular communication scheme, the radiocommunication interface 1612 can support additional types of radiocommunication schemes, such as short-range wireless communicationschemes, near field communication schemes, and wireless local areanetwork (LAN) schemes. In this situation, the radio communicationinterface 1612 can include the BB processor 1613 and the RF circuitry1614 for each radio communication scheme.

Each of the antenna switches 1615 switches destinations to connect theantenna 1616 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 1612.

Each of the antennas 1616 includes a single antenna element or multipleantenna elements (such as multiple antenna elements included in a MIMOantenna) and is used for the radio communication interface 1612 totransmit and receive radio signals. The smartphone 1600 can includemultiple antennas 1616, as illustrated in FIG. 16. Although FIG. 16illustrates the example in which the smartphone 1600 includes multipleantennas 1616, the smartphone 1600 can also include a single antenna1616.

Furthermore, the smartphone 1600 can include the antennas 1616 for eachradio communication scheme. In this situation, the antenna switch 1615can be omitted from the configuration of the smartphone 1600.

The bus 1617 connects the processor 1601, the memory 1602, the storage1603, the external connection interface 1604, the camera 1606, thesensor 1607, the microphone 1608, the input device 1609, the displaydevice 1610, the speaker 1611, the radio communication interface 1612,and the auxiliary control 1619 to each other. The battery 1618 suppliespower to modules of the smartphone 1600 illustrated in FIG. 16 viafeeder lines, which are partially shown as dashed lines in the figure.The auxiliary controller 1619 operates minimum necessary functions ofthe smartphone 1600, for example, in a sleep mode.

Second Application Example

FIG. 17 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 1720 to which the technologyherein can be applied. The car navigation device 1720 includes aprocessor 1721, a memory 1722, a global positioning system (GPS) module1724, a sensor 1725, a data interface 1726, a content player 1727, astorage medium interface 1728, an input device 1729, a display device1730, a speaker 1731, and a radio communication interface 1733, one ormore antenna switches 1736, one or more antennas 1737, and a battery1738. In one implementation, the car navigation device 1720 (orprocessor 1721) herein can correspond to the transmitting endcommunication device 400 described above. In another implementation, thecar navigation device 1720 (or processor 1721) can correspond to thereceiving end communication device 500 described above.

The processor 1721 can be, for example, a CPU or a SoC, and controls anavigation function and other functions of the car navigation device1720. The memory 1722 includes RAM and ROM, and stores a program that isexecuted by the processor 1721 and data.

The GPS module 1724 uses GPS signals received from a GPS satellite tomeasure a position, such as latitude, longitude, and altitude, of thecar navigation device 1720. The sensor 1725 can include a group ofsensors such as a gyro sensor, a geomagnetic sensor, and an air pressuresensor. The data interface 1726 is connected to, for example, anin-vehicle network 1741 via a terminal (not shown), and acquires datagenerated by the vehicle, such as vehicle speed data.

The content player 1727 reproduces content stored in a storage medium(such as a CD and a DVD) that is inserted into the storage mediuminterface 1728. The input device 1729 includes, for example, a touchsensor configured to detect touch on a screen of the display device1730, a button, or a switch, and receives an operation or an informationinput from a user. The display device 1730 includes a screen such as anLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 1731 outputs sounds of thenavigation function or the content that is reproduced.

The radio communication interface 1733 supports any cellularcommunication scheme, such as LTE and LTE-Advanced, and performs radiocommunication. The radio communication interface 1733 can typicallyinclude, for example, a BB processor 1734 and an RF circuit 1735. The BBprocessor 1734 can perform, for example, encoding/decoding,modulation/demodulation, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 1735 can include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna1737. The radio communication interface 1733 can also be a one chipmodule which integrates the BB processor 1734 and the RF circuit 1735thereon. The radio communication interface 1733 can include multiple BBprocessors 1734 and multiple RF circuits 1735, as illustrated in FIG.17. Although FIG. 17 illustrates the example in which the radiocommunication interface 1733 includes multiple BB processors 1734 andmultiple RF circuits 1735, the radio communication interface 1733 canalso include a single BB processor 1734 or a single RF circuit 1735.

Furthermore, in addition to the cellular communication scheme, the radiocommunication interface 1733 can support another types of radiocommunication schemes such as a short-range wireless communicationscheme, a near-field communication scheme, and a wireless LAN scheme. Inthis situation, the radio communication interface 1733 can include theBB processor 1734 and the RF circuit 1735 for each radio communicationscheme.

Each of the antenna switches 1736 switches destinations to connect theantenna 1737 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 1733.

Each of the antennas 1737 includes a single antenna element or multipleantenna elements, such as the multiple antenna elements included in aMIMO antenna, and is used for the radio communication interface 1733 totransmit and receive radio signals. The car navigation device 1720 caninclude multiple antennas 1737, as illustrated in FIG. 17. Although FIG.17 illustrates the example in which the car navigation device 1720includes multiple antennas 1737, the car navigation device 1720 caninclude a single antenna 1737.

Furthermore, the car navigation device 1720 can include the antenna 1737for each radio communication scheme. In this situation, the antennaswitch 1736 can be omitted from the configuration of the car navigationdevice 1720.

The battery 1738 supplies power to modules of the car navigation device1720 illustrated in FIG. 17 via feeder lines that are partially shown asdashed lines in the figure. The battery 1738 accumulates power suppliedfrom the vehicle.

The technology herein can also be implemented as an in-vehicle system(or vehicle) 1740 including one or more modules of the car navigationdevice 1720, an in-vehicle network 1741, and a vehicle module 1742. Thevehicle module 1742 generates vehicle data such as vehicle speed, enginespeed, and faults information, and outputs the generated data to thein-vehicle network 1741.

Although the illustrative embodiments of the present disclosure havebeen described with reference to the accompanying drawings, the presentdisclosure is, of course, not limited to the above examples. Thoseskilled in the art can achieve various adaptions and modificationswithin the scope of the appended claims, and it will be appreciated thatthese adaptions and modifications, of course, fall into the scope of thetechnology of the present disclosure.

For example, in the above embodiments, the multiple functions includedin one module can be implemented by separate means. Alternatively, inthe above embodiments, the multiple functions included in multiplemodules can be implemented by separate means, respectively. Inadditions, one of the above functions can be implemented by multipleunits. Needless to say, such configurations fall within the scope of thetechnology of the present disclosure.

In this specification, the steps described in the flowcharts include notonly the processes performed sequentially in chronological order, butalso the processes performed in parallel or separately but notnecessarily performed in chronological order. Furthermore, even in thesteps performed in chronological order, needless to say, the order canbe changed appropriately.

Although the present disclosure and its advantages have been describedin detail, it will be appreciated that various changes, replacements andtransformations can be made without departing from the spirit and scopeof the present disclosure as defined by the appended claims. Inaddition, the terms “include”, “comprise” or any other variants of theembodiments of the present disclosure are intended to be non-exclusiveinclusion, such that the process, method, article or device including aseries of elements includes not only these elements, but also those thatare not listed specifically, or those that are inherent to the process,method, article or device. In case of further limitations, the elementdefined by the sentence “include one” does not exclude the presence ofadditional same elements in the process, method, article or deviceincluding this element.

What is claimed is:
 1. A communication device, comprising: a processingcircuit, configured to: perform successive interference cancellation ona received transmission signal, detect signals for other communicationdevices and cancel the detected signals as interference, until amodulation symbol for the communication device per se is detected and asequence number of a first channel that has transmitted the receivedtransmission signal is detected; and map the sequence number of thefirst channel to a first portion of information bits for thecommunication device per se based on a predetermined mapping rule, anddetermine a second portion of information bits for the communicationdevice per se based on the modulation symbol for the communicationdevice per se.
 2. The communication device according to claim 1, whereinthe sequence number of the first channel corresponds to a sequencenumber of a first antenna.
 3. The communication device according toclaim 1, wherein the sequence number of the first channel is detectedbased on channel state information which is determined by thecommunication device based on a training sequence transmitted over thefirst channel
 4. The communication device according to claim 1, whereinthe processing circuit is further configured to: receive information onamplitude phase modulation scheme, and determine the second portion ofinformation bits for the communication device per se by using theamplitude phase modulation scheme indicated by the information onamplitude phase modulation scheme.
 5. The communication device of claim1, wherein the processing circuit is further configured to: receiveinformation indicative of an order of a transmission power used fortransmission of a signal for the communication device per se over thefirst channel in transmission powers used for transmission of signalsfor all the communication devices or indicative of a demodulation order,wherein a number of times the successive interference cancellation isperformed depends on the order or the demodulation order.
 6. Thecommunication device of claim 2, wherein the processing circuit isfurther configured to: in the successive interference cancellation, thesignals for the other communication devices are detected by a detectionalgorithm, the detection algorithm comprises a maximum likelihoodalgorithm or a maximum ratio combining algorithm.
 7. The communicationdevice according to claim 1, wherein the processing circuit isconfigured to: combine the first portion of information bits for thecommunication device per se and the second portion of information bitsfor the communication device per se into an original transmission dataflow.
 8. The communication device according to claim 1, furthercomprising a memory configured to store the predetermined mapping rulefor the processing circuit to read, wherein the predetermined mappingrule specifies mapping relation between the first portion of informationbits and the sequence number of the first channel
 9. A method performedby a communication device, comprising: performing successiveinterference cancellation on a received transmission signal, detectingsignals for other communication devices and cancelling the detectedsignals as interference, until a modulation symbol for the communicationdevice per se is detected and a sequence number of a first channel thathas transmitted the received transmission signal is detected; andmapping the sequence number of the first channel to a first portion ofinformation bits for the communication device per se based on apredetermined mapping rule, and determining a second portion ofinformation bits for the communication device per se based on themodulation symbol for the communication device per se.